OFFSET
1,2
FORMULA
G.f.: (1/(1 - x)) * Sum_{j>=1} Sum{k>=1} k^j * x^(k*(2*j-1)) * (1 - x^(2*j-1)).
Limit_{n->infinity} a(n)^(1/n) = exp(exp(-1)/2). - Vaclav Kotesovec, Dec 17 2021
MATHEMATICA
a[n_] := Sum[Floor[n/(2*k - 1)]^k, {k, 1, n}]; Array[a, 50] (* Amiram Eldar, Dec 17 2021 *)
PROG
(PARI) a(n) = sum(k=1, n, (n\(2*k-1))^k);
(PARI) my(N=66, x='x+O('x^N)); Vec(sum(j=1, N, (1-x^(2*j-1))*sum(k=1, N, k^j*x^(k*(2*j-1))))/(1-x))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Dec 16 2021
STATUS
approved