OFFSET
1,3
MATHEMATICA
a[n_] := a[n] = Sum[Binomial[n - 1, d] a[d], {d, Divisors[n - 1]}]; a[1] = 1; Table[a[n], {n, 1, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 27 2019
STATUS
approved