A035200 Coefficients in expansion of Dirichlet series Product_p (1-(Kronecker(m,p)+1)*p^(-s)+Kronecker(m,p)*p^(-2s))^(-1) for m = 18.

1, 1, 1, 1, 0, 1, 2, 1, 1, 0, 0, 1, 0, 2, 0, 1, 2, 1, 0, 0, 2, 0, 2, 1, 1, 0, 1, 2, 0, 0, 2, 1, 0, 2, 0, 1, 0, 0, 0, 0, 2, 2, 0, 0, 0, 2, 2, 1, 3, 1, 2, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0, 2, 2, 1, 0, 0, 0, 2, 2, 0, 2, 1, 2, 0, 1, 0, 0, 0, 2, 0, 1

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy
• mult

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001132, A003629.

Programs

Mathematica

a[n_] := DivisorSum[n, KroneckerSymbol[18, #] &]; Array[a, 100] (* Amiram Eldar, Nov 19 2023 *)

PARI

my(m = 18); direuler(p=2,101,1/(1-(kronecker(m,p)*(X-X^2))-X))

PARI

a(n) = sumdiv(n, d, kronecker(18, d)); \\ Amiram Eldar, Nov 19 2023

Formula

From Amiram Eldar, Nov 19 2023: (Start)

a(n) = Sum_{d|n} Kronecker(18, d).

Multiplicative with a(p^e) = 1 if Kronecker(18, p) = 0 (p = 2 or 3), a(p^e) = (1+(-1)^e)/2 if Kronecker(18, p) = -1 (p is in A003629 \ {3}), and a(p^e) = e+1 if Kronecker(18, p) = 1 (p is in A001132).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 4*log(sqrt(2)+1)/(3*sqrt(2)) = 0.830966986853... . (End)