A364092 Sum of divisors of 5*n-1 of form 5*k+1.

1, 1, 1, 1, 7, 1, 1, 1, 12, 1, 7, 1, 17, 1, 1, 1, 28, 1, 1, 12, 27, 1, 7, 1, 32, 1, 1, 1, 59, 1, 12, 1, 42, 1, 7, 1, 47, 22, 1, 1, 58, 12, 1, 1, 73, 1, 33, 1, 62, 1, 1, 1, 84, 1, 1, 32, 72, 1, 28, 1, 93, 1, 1, 12, 124, 1, 1, 1, 87, 1, 7, 1, 118, 42, 12, 1, 119, 1, 1, 22, 102, 1, 53, 1, 107, 12, 32, 1

Offset

1,5

Links

Table of n, a(n) for n=1..88.

Formula

a(n) = A284097(5*n-1).

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

Mathematica

a[n_] := DivisorSum[5*n - 1, # &, Mod[#, 5] == 1 &]; Array[a, 100] (* Amiram Eldar, Jul 17 2023 *)

Prog

(PARI) a(n) = sumdiv(5*n-1, d, (d%5==1)*d);

Crossrefs

Cf. A364093, A364094, A364095.

Cf. A008438, A363514.

Cf. A284097, A359233, A364096.

Sequence in context: A214685 A327670 A178637 * A295294 A317936 A277875

Adjacent sequences: A364089 A364090 A364091 * A364093 A364094 A364095

Keyword

nonn

Author

Seiichi Manyama, Jul 04 2023

Status

approved