OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..1001
FORMULA
a(1) = 1; a(n) = -Sum_{d|n, d < n} A000108(n/d) * a(d).
G.f. A(x) satisfies: A(x) = x - Sum_{k>=2} Catalan(k) * A(x^k). - Ilya Gutkovskiy, Feb 23 2022
MATHEMATICA
a[1] = 1; a[n_] := a[n] = -DivisorSum[n, a[#] * CatalanNumber[n/#] &, # < n &]; Array[a, 30] (* Amiram Eldar, Nov 22 2021 *)
PROG
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, Nov 22 2021
STATUS
approved