OFFSET
1
COMMENTS
Of the first 10000 terms, 2540 are 0's and 7460's are 1's. Even n such that a(n) = 0 are rare: 2, 10, 50, 98, 154, 266, 374, 598, 770, 1054, 1250, 1558, 2162, 2662, 3422, 4154, 5390, 5402, 6578, 6806, 8342, 8918, 9682 are all such n less than 10001.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000 (based on Hans Havermann's factorization of A156552)
FORMULA
PROG
(PARI)
\\ Needs code also from A323243.
A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Mar 28 2019
STATUS
approved