OFFSET
0,6
FORMULA
G.f.: 1 / (1 + Sum_{k>=1} x^(k^2) / (1 - x^k)).
a(0) = 1; a(n) = -Sum_{k=1..n} A038548(k) * a(n-k).
MATHEMATICA
nmax = 53; CoefficientList[Series[1/(1 + Sum[x^(k^2)/(1 - x^k), {k, 1, nmax}]), {x, 0, nmax}], x]
a[0] = 1; a[n_] := a[n] = -Sum[Floor[(DivisorSigma[0, k] + 1)/2] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 53}]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Sep 25 2019
STATUS
approved