A359324 Number of divisors of 6*n-2 of form 6*k+5.

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

Offset: 1

Author

Seiichi Manyama, Dec 25 2022

Keywords

• nonn
• easy

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A319995, A359305, A359325, A359326, A359327.

Cf. A359239, A359269, A359290.

Programs

Mathematica

a[n_] := DivisorSum[6*n-2, 1 &, Mod[#, 6] == 5 &]; Array[a, 100] (* Amiram Eldar, Aug 14 2023 *)

PARI

a(n) = sumdiv(6*n-2, d, d%6==5);

PARI

my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(2*k)/(1-x^(6*k-1)))))

PARI

my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(5*k-3)/(1-x^(6*k-4)))))

Formula

a(n) = A319995(6*n-2).

G.f.: Sum_{k>0} x^(2*k)/(1 - x^(6*k-1)).

G.f.: Sum_{k>0} x^(5*k-3)/(1 - x^(6*k-4)).