OFFSET
1,3
COMMENTS
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..10000
Eric Angelini, Michael S. Branicky, Giovanni Resta, N. J. A. Sloane, and David W. Wilson, The Comma Sequence: A Simple Sequence With Bizarre Properties, arXiv:2401.14346, Youtube
FORMULA
a(n) ~ n*(log(2*n)/2 + gamma - 1/2), where gamma is the Euler-Mascheroni constant A001620. - Vaclav Kotesovec, Jan 08 2024
PROG
(PARI) f(n) = numdiv(n>>valuation(n, 2)) - ispolygonal(n, 3); \\ A136107
a(n) = sum(k=1, n, f(k)); \\ Michel Marcus, Jan 08 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 08 2024
STATUS
approved