OFFSET
1,2
FORMULA
G.f.: Sum_{k>0} 2^(k-1)*x^k/(1-2*x^k). - Vladeta Jovovic, Jun 24 2003
a(n) ~ 2^n. - Vaclav Kotesovec, Sep 11 2019
MATHEMATICA
Table[Sum[2^(d + n/d - 2), {d, Divisors[n]}], {n, 1, 30}] (* Vaclav Kotesovec, Sep 11 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved