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Revision History for A023758

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Showing entries 1-10 | older changes
A023758 Numbers of the form 2^i - 2^j with i >= j.
(history; published version)
#154 by Alois P. Heinz at Fri Nov 03 06:38:38 EDT 2023
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reviewed

approved

#153 by Michel Marcus at Fri Nov 03 06:37:54 EDT 2023
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proposed

reviewed

#152 by Jon E. Schoenfield at Fri Nov 03 06:33:10 EDT 2023
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editing

proposed

#151 by Jon E. Schoenfield at Fri Nov 03 06:33:06 EDT 2023
LINKS

T. D. Noe andReinhard R. Zumkeller, <a href="/A023758/b023758.txt">Table of n, a(n) for n = 1..10000</a>, First> (first 5051 terms from T. D. Noe)

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approved

editing

#150 by N. J. A. Sloane at Sat Feb 04 20:43:49 EST 2023
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proposed

approved

#149 by Michel Marcus at Sat Feb 04 02:11:10 EST 2023
STATUS

editing

proposed

Discussion
Sat Feb 04 08:51
Lorenzo Sauras Altuzarra: Yes, thank you!
#148 by Michel Marcus at Sat Feb 04 02:10:46 EST 2023
COMMENTS

If v is the dyadic valuation (i.e., A007814), then A002260(n) = v(a(n)/2^v(a(n))+1) and A002024(n) = A002260(n) + v(a(n)). - _)) where v is the dyadic valuation (i.e., A007814). - _Lorenzo Sauras Altuzarra_, Feb 01 2023

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proposed

editing

Discussion
Sat Feb 04 02:11
Michel Marcus: ok like this ?
#147 by Jon E. Schoenfield at Fri Feb 03 20:00:13 EST 2023
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editing

proposed

#146 by Jon E. Schoenfield at Fri Feb 03 20:00:10 EST 2023
COMMENTS

Subset of A077436. Proof: Since a(n) is of the form (2^i-1))*2^j, i,j>= >= 0, a(n)^2 = [ = (2^(2i)-) - 2^(i+1)]))*2^(2j) + 2^(2j) where the first sum term has i-1 one bits and its 2j-th bit is zero, while the second sum term switches the 2j-th bit to one, giving i one bits, as in a(n). - Ralf Stephan, Mar 08 2004

Numbers n such thatwhose binary representation contains no "01". - Benoit Cloitre, May 23 2004

Powers of 2 represented in bases which are membersterms of this sequence must always contain at least one digit which is also a power of 2. This is because 2^i mod (2^i - 2^j) = 2^j, which means the last digit always cycles through powers of 2 (or if i=j+1 then the first digit is a power of 2 and the rest are trailing zeros). The only known non-member of this sequence with this property is 5. - Ely Golden, Sep 05 2017

Numbers nk such that nk = 2^(1 + A000523(nk)) - 2^A007814(nk). - Daniel Starodubtsev, Aug 05 2021

If v is the dyadic valuation (i.e. ., A007814), then A002260(n) = v(a(n)/2^v(a(n))+1) and A002024(n) = A002260(n) + v(a(n)). - Lorenzo Sauras Altuzarra, Feb 01 2023

FORMULA

Start with A000225. If nk is in the sequence, then so is 2n2k. - Ralf Stephan, Aug 16 2013

A277699(a(n)) = a(n)^2, A306441(a(n)) = a(n+1). - Antti Karttunen, Feb 15 2021 (the latter identity from A306441).)

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proposed

editing

#145 by Lorenzo Sauras Altuzarra at Fri Feb 03 19:14:48 EST 2023
STATUS

editing

proposed

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Last modified September 8 17:50 EDT 2024. Contains 375753 sequences. (Running on oeis4.)