OFFSET
1,9
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
L.g.f.: log(Product_{n>=1} (1 - a(n)*x^n)^(1/n)) = Sum_{n>=1} a(n+1)*x^n/n.
MAPLE
f:= proc(n) option remember; local d;
-add(procname(d)^((n-1)/d), d = numtheory:-divisors(n-1))
end proc:
f(1):= 1:
map(f, [$1..100]); # Robert Israel, Apr 29 2019
MATHEMATICA
a[n_] := a[n] = -Sum[a[d]^((n - 1)/d), {d, Divisors[n - 1]}]; a[1] = 1; Table[a[n], {n, 1, 60}]
PROG
(PARI) lista(nn) = {my(va = vector(nn)); va[1] = 1; for (n=2, nn, va[n] = -sumdiv(n-1, d, va[d]^((n-1)/d)); ); va; } \\ Michel Marcus, Apr 30 2019
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Apr 28 2019
STATUS
approved