OFFSET
0,5
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: (Sum_{k>=1} mu(k) * x^k) / (1 - 2*x).
a(n) = 2 * a(n-1) + mu(n) for n > 0.
a(n) ~ A238270 * 2^n. - Vaclav Kotesovec, May 19 2021
MATHEMATICA
a[n_] := Sum[MoebiusMu[k] * 2^(n-k), {k, 1, n}]; Array[a, 40] (* Amiram Eldar, May 19 2021 *)
PROG
(PARI) a(n) = sum(k=1, n, moebius(k)*2^(n-k));
(PARI) my(N=40, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, moebius(k)*x^k)/(1-2*x)))
(PARI) a(n) = if(n==0, 0, 2*a(n-1)+moebius(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 19 2021
STATUS
approved