A320781 Inverse Euler transform of the Moebius function A008683.

1, -2, 0, 0, -1, 2, -4, 5, -7, 9, -10, 7, -5, -2, 19, -44, 70, -103, 138, -166, 154, -83, -70, 346, -797, 1413, -2160, 2931, -3479, 3380, -2080, -1259, 7593, -17743, 32014, -49818, 68683, -82985, 82807, -53462, -24942, 176139, -422887, 777357, -1226688

Offset: 1

Author

Gus Wiseman, Oct 22 2018

Keywords

• sign

Comments

The Euler transform of a sequence q is the sequence of coefficients of x^n, n > 0, in the expansion of Product_{n > 0} 1/(1 - x^n)^q(n).

Links

• OEIS Wiki, Euler transform

Crossrefs

Cf. A008683,

Programs

Maple

# The function EulerInvTransform is defined in A358451.
a := EulerInvTransform(n -> ifelse(n=0, 1, NumberTheory:-Moebius(n))):
seq(a(n), n = 1..45); # Peter Luschny, Nov 21 2022

Mathematica

EulerInvTransform[{}]={};EulerInvTransform[seq_]:=Module[{final={}},For[i=1,i<=Length[seq],i++,AppendTo[final,i*seq[[i]]-Sum[final[[d]]*seq[[i-d]],{d,i-1}]]];
Table[Sum[MoebiusMu[i/d]*final[[d]],{d,Divisors[i]}]/i,{i,Length[seq]}]];
EulerInvTransform[Table[MoebiusMu[n],{n,30}]]

Python

from functools import lru_cache
from sympy import mobius, divisors
def A320781(n):
    @lru_cache(maxsize=None)
    def b(n): return mobius(n)
    @lru_cache(maxsize=None)
    def c(n): return n*b(n)-sum(c(k)*b(n-k) for k in range(1,n))
    return sum(b(d)*c(n//d) for d in divisors(n,generator=True))//n # Chai Wah Wu, Jul 15 2024