A359306 Number of divisors of 6*n-2 of form 6*k+1.

1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 2, 3, 1, 2, 1, 2, 1, 1, 2, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 1, 1, 2, 1, 1, 1, 4, 2, 1, 1, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 1, 2, 3, 2, 1, 2, 1, 2, 1, 4, 1

Offset

1,5

Links

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

Formula

a(n) = A279060(6*n-2).

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

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

Mathematica

a[n_] := DivisorSum[6*n-2, 1 &, Mod[#, 6] == 1 &]; Array[a, 100] (* Amiram Eldar, Aug 16 2023 *)

Prog

(PARI) a(n) = sumdiv(6*n-2, d, d%6==1);
(PARI) my(N=100, x='x+O('x^N)); Vec(sum(k=1, N, x^k/(1-x^(6*k-2))))
(PARI) my(N=100, x='x+O('x^N)); Vec(sum(k=1, N, x^(4*k-3)/(1-x^(6*k-5))))

Crossrefs

Cf. A279060, A359305, A359307, A359308, A359309.

Sequence in context: A220464 A215975 A071891 * A332761 A046072 A072273

Adjacent sequences: A359303 A359304 A359305 * A359307 A359308 A359309

Keyword

nonn,easy

Author

Seiichi Manyama, Dec 25 2022

Status

approved