OFFSET
0,5
COMMENTS
Invert transform of A032741.
LINKS
Robert Israel, Table of n, a(n) for n = 0..3000
FORMULA
G.f.: 1 / (1 - Sum_{k>=1} x^(2*k) / (1 - x^k)).
a(0) = 1; a(n) = Sum_{k=1..n} A032741(k) * a(n-k).
MAPLE
N:= 100: # for a(0)..a(N)
G:= 1/(1-add(x^(2*k)/(1-x^k), k=1..(N+1)/2)):
S:= series(G, x, N+1):
seq(coeff(S, x, i), i=0..N); # Robert Israel, Jan 10 2023
MATHEMATICA
nmax = 38; CoefficientList[Series[1/(1 - Sum[x^(2 k)/(1 - x^k), {k, 1, nmax}]), {x, 0, nmax}], x]
a[0] = 1; a[n_] := a[n] = Sum[(DivisorSigma[0, k] - 1) a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 38}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 25 2019
STATUS
approved