A305610 - OEIS

A305610

a(n) = (-1)^(n-1) + Sum_{d|n, d>1} binomial(a(n/d) + d - 1, d).

1, 0, 2, 0, 2, 3, 2, 0, 6, 3, 2, 11, 2, 3, 12, 0, 2, 38, 2, 11, 14, 3, 2, 90, 8, 3, 68, 11, 2, 127, 2, 0, 18, 3, 16, 1194, 2, 3, 20, 90, 2, 173, 2, 11, 644, 3, 2, 5158, 10, 68, 24, 11, 2, 12762, 20, 90, 26, 3, 2, 12910, 2, 3, 1386, 0, 22, 289, 2, 11, 30, 219, 2

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

MATHEMATICA

a[n_]:=a[n]=(-1)^(n-1)+Sum[Binomial[a[n/d]+d-1, d], {d, Divisors[n]//Rest}];

Array[a, 40]

PROG

(PARI) A305610(n) = ((-1)^(n-1) + sumdiv(n, d, if(d==1, 0, binomial(A305610(n/d)+d-1, d)))); \\ Antti Karttunen, Dec 05 2021

CROSSREFS