A363407 Sum of divisors of 4*n-3 of form 4*k+3.

0, 0, 3, 0, 0, 10, 0, 0, 14, 0, 0, 18, 7, 0, 22, 0, 0, 26, 0, 18, 30, 0, 0, 34, 0, 0, 60, 0, 0, 42, 11, 0, 46, 26, 0, 50, 0, 0, 54, 0, 30, 84, 0, 0, 62, 0, 0, 100, 0, 0, 70, 0, 30, 74, 38, 0, 93, 0, 0, 82, 0, 42, 86, 34, 0, 90, 0, 0, 140, 0, 0, 132, 0, 0, 140, 50, 0, 106, 0, 0, 110, 0, 54, 114, 0, 42, 156

Offset

1,3

Links

Table of n, a(n) for n=1..87.

Formula

a(n) = A050452(4*n-3).

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

Mathematica

a[n_] := DivisorSum[4*n - 3, # &, Mod[#, 4] == 3 &]; Array[a, 100] (* Amiram Eldar, Jul 08 2023 *)

Prog

(PARI) a(n) = sumdiv(4*n-3, d, (d%4==3)*d);

Crossrefs

Cf. A050452, A359240, A364084.

Sequence in context: A177016 A346811 A244127 * A342312 A123474 A370064

Adjacent sequences: A363404 A363405 A363406 * A363408 A363409 A363410

Keyword

nonn

Author

Seiichi Manyama, Jul 08 2023

Status

approved