A363035 - OEIS

A363035

Sum of divisors of 5*n-3 of form 5*k+3.

0, 0, 3, 0, 0, 3, 8, 0, 3, 0, 13, 3, 0, 0, 29, 0, 0, 3, 23, 0, 3, 0, 36, 16, 0, 0, 36, 0, 0, 3, 46, 0, 21, 0, 43, 3, 13, 0, 59, 0, 0, 26, 53, 0, 3, 0, 66, 3, 0, 13, 112, 0, 0, 3, 76, 0, 3, 0, 73, 36, 0, 0, 102, 0, 23, 3, 83, 0, 59, 0, 96, 3, 0, 0, 96, 13, 0, 46, 134, 0, 3, 0, 103, 3, 0, 0, 185, 23, 13, 3, 113, 0, 36

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..93.

FORMULA

a(n) = A284281(5*n-3).

G.f.: Sum_{k>0} (5*k-2) * x^(4*k-1) / (1 - x^(5*k-2)).

MATHEMATICA

a[n_] := DivisorSum[5*n - 3, # &, Mod[#, 5] == 3 &]; Array[a, 100] (* Amiram Eldar, Jul 06 2023 *)

PROG

(PARI) a(n) = sumdiv(5*n-3, d, (d%5==3)*d);