OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..6911
FORMULA
a(n) = Sum_t (-1)^(n-k) where the sum is over all same-trees of weight n (see A281145 for definition) and k is the number of leaves.
MATHEMATICA
a[n_]:=a[n]=(-1)^(n-1)+Sum[a[n/y]^y, {y, Divisors[n]//Rest}];
Array[a, 40]
PROG
(PARI) A305572(n) = ((-1)^(n-1) + sumdiv(n, d, if(d==1, 0, A305572(n/d)^d))); \\ Antti Karttunen, Dec 05 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 05 2018
STATUS
approved