Revision History for A247473
(Underlined text is an addition;
strikethrough text is a deletion.)
Showing entries 1-10
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#37 by Charles R Greathouse IV at Thu Sep 08 08:46:09 EDT 2022
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| PROG
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(MAGMAMagma) Set(Sort([SumOfDivisors(n): n in [A046528(n)]]))
(MAGMAMagma) Set(Sort([SumOfDivisors(n): n in[1..10000], k in [0..100] | SumOfDivisors(n) eq 2^k]))
(MAGMAMagma) [1] cat [2^n: n in[A180221(n)]]
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Discussion
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| Thu Sep 08
| 08:46
| OEIS Server: https://oeis.org/edit/global/2944
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#36 by N. J. A. Sloane at Mon Mar 09 23:06:52 EDT 2015
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#35 by Robert G. Wilson v at Fri Feb 27 09:36:39 EST 2015
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#34 by Jaroslav Krizek at Fri Feb 27 09:07:12 EST 2015
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#33 by Jaroslav Krizek at Fri Feb 27 09:07:06 EST 2015
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| NAME
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allocatedNumbers of the form 2^k (k>=0) that are a sum of divisors of n for Jaroslavsome Krizekn.
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| DATA
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1, 4, 8, 32, 128, 256, 512, 1024, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648, 4294967296, 8589934592, 17179869184, 34359738368
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| OFFSET
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1,2
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| COMMENTS
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Set of values A094502(n) = sigma(A046528(n)) in increasing order.
Complement of A094505 with respect to A000079 (powers of 2).
Corresponding values of numbers k>0 are in A180221.
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| FORMULA
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a(1) = 1, for n>=2, a(n) = 2^A180221(n-1).
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| EXAMPLE
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32 = 2^5 is in sequence because there are numbers n = 21 and 31 with sigma(n) = 32.
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| PROG
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(MAGMA) Set(Sort([SumOfDivisors(n): n in [A046528(n)]]))
(MAGMA) Set(Sort([SumOfDivisors(n): n in[1..10000], k in [0..100] | SumOfDivisors(n) eq 2^k]))
(MAGMA) [1] cat [2^n: n in[A180221(n)]]
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| CROSSREFS
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Cf. A000079, A000203, A046528, A078426, A094502, A094505, A180221.
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| KEYWORD
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allocated
nonn
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| AUTHOR
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Jaroslav Krizek, Feb 27 2015
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| STATUS
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approved
editing
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#32 by Jaroslav Krizek at Fri Feb 27 08:37:54 EST 2015
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| NAME
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allocated for Jaroslav Krizek
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| KEYWORD
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recycled
allocated
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#31 by Joerg Arndt at Fri Feb 27 06:05:13 EST 2015
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#30 by Joerg Arndt at Fri Feb 27 06:05:07 EST 2015
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| NAME
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Mersenne primes: 2^p-1 constructed with p=n^2 + n + 1 = A002383(n)
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| DATA
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3, 7, 13, 31, 4423
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| OFFSET
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1,1
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| COMMENTS
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for n=1,2,3,5 and 66
Definition: Exponent of 2^p(n)-1 is
p(n)=n^2+n+1 and p(n) a prime number of Mersenne prime
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| LINKS
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A. Lamek, <a href="/A247473/b247473.txt">Table of n, a(n) for n = 1..5</a>
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| FORMULA
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2^p(n)-1 --> p(n)=n^2 + n + 1
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| EXAMPLE
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for n=1, p(1)=1^2+1+1=3
for n=66, p(66)=66^2+66+1=4423
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| CROSSREFS
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A002383
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| KEYWORD
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nonn,hard
recycled
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| AUTHOR
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A. Lamek, Dec 02 2014
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| STATUS
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proposed
editing
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#29 by A. Lamek at Fri Jan 30 11:27:45 EST 2015
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Discussion
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| Sat Jan 31
| 12:10
| N. J. A. Sloane: SUGGEST RESUBMIT LATER
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| Fri Feb 27
| 06:04
| Joerg Arndt: Thank you for your proposed contribution. Unfortunately, the OEIS has such
a backlog of contributions waiting to be processed that for the next two or
three months we will only consider new sequences or comments, formulas,
etc. of the very highest quality. Please resubmit your contribution at a
later time. - The Editors of the OEIS.
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#28 by A. Lamek at Thu Jan 22 14:19:24 EST 2015
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| NAME
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Mersenne primes: 2^p-1 constructed with p=n^2 + n + 1 = A002383(n)
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| COMMENTS
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Definition: Exponent of 2^p(n)-1 is
p(n)=n^2+n+1 and p(n) a prime number of Mersenne prime 2^p(n)-1
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| FORMULA
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2^p(n)-1 --> p(n)=n^2 + n + 1
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Discussion
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| Thu Jan 29
| 16:03
| OEIS Server: This sequence has not been edited or commented on for a week
yet is not proposed for review. If it is ready for review, please
visit https://oeis.org/draft/A247473 and click the button that reads
"These changes are ready for review by an OEIS Editor."
Thanks.
- The OEIS Server
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