|
| |
|
|
A213671
|
|
The odd part of n^2 - n + 2.
|
|
3
|
|
|
|
1, 1, 1, 7, 11, 1, 11, 29, 37, 23, 7, 67, 79, 23, 53, 121, 137, 77, 43, 191, 211, 29, 127, 277, 301, 163, 11, 379, 407, 109, 233, 497, 529, 281, 149, 631, 667, 11, 371, 781, 821, 431, 113, 947, 991, 259, 541, 1129, 1177, 613, 319, 1327, 1379, 179
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,4
|
|
|
COMMENTS
|
The first composite term s of this sequence which is not multiple of a prime term appeared before s is a(245) = 29891 = 71*421 - neither of 71, 421 are terms before a(245). - Peter J. C. Moses, Mar 03 2013
The probability that n points uniformly distributed in (or on) a sphere are in the same hemisphere is (n^2-n+2)/2^n, for which this is the numerator. - Charles R Greathouse IV, Sep 18 2013
|
|
|
LINKS
|
|
|
|
FORMULA
|
|
|
|
MAPLE
|
|
|
|
MATHEMATICA
|
Table[k = n^2 - n + 2; k/2^IntegerExponent[k, 2], {n, 100}] (* T. D. Noe, Mar 16 2013 *)
|
|
|
PROG
|
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn,easy
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
