OFFSET
1,2
COMMENTS
LINKS
N. J. A. Sloane, Table of n, a(n) for n = 1..5000
FORMULA
From Amiram Eldar, Jan 18 2024: (Start)
a(n) = A137921(2*n).
Sum_{k=1..n} a(k) ~ (n/2) * (3*log(n) + 6*gamma - 7 + log(2)), where gamma is Euler's constant (A001620). (End)
PROG
(PARI) a(n) = sumdiv(2*n, d, ((2*n)%(d+1) != 0)); \\ Amiram Eldar, Jan 18 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 26 2010
STATUS
approved