A363877 Number of divisors of 7*n-2 of form 7*k+3.

0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 2, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 3, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 3, 0, 0, 1, 1, 0, 2, 0, 2, 1, 0, 1, 2, 0, 0, 1, 1, 0, 2, 0, 1, 1, 1, 1, 3, 0, 0, 1, 2, 0, 1, 0, 1, 2, 0, 0, 2, 0, 1, 1, 2, 0, 2, 0, 2, 1, 0, 0, 4, 0, 0, 1, 1, 0, 1, 1, 1, 2, 1, 0, 3, 0, 0

Offset

1,14

Comments

Also number of divisors of 7*n-2 of form 7*k+4.

Links

Table of n, a(n) for n=1..100.

Formula

a(n) = A363805(7*n-2) = A363806(7*n-2).

G.f.: Sum_{k>0} x^(4*k-2)/(1 - x^(7*k-4)).

G.f.: Sum_{k>0} x^(3*k-1)/(1 - x^(7*k-3)).

Mathematica

a[n_] := DivisorSum[7*n - 2, 1 &, Mod[#, 7] == 3 &]; Array[a, 100] (* Amiram Eldar, Jun 25 2023 *)

Prog

(PARI) a(n) = sumdiv(7*n-2, d, d%7==3);

Crossrefs

Cf. A363805, A353806.

Sequence in context: A362983 A352822 A090418 * A322452 A076754 A346482

Adjacent sequences: A363874 A363875 A363876 * A363878 A363879 A363880

Keyword

nonn

Author

Seiichi Manyama, Jun 25 2023

Status

approved