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A364101
Sum of divisors of 5*n-2 of form 5*k+4.
4
0, 4, 0, 9, 0, 18, 0, 19, 0, 28, 0, 29, 9, 38, 0, 39, 0, 48, 0, 63, 0, 67, 0, 59, 0, 68, 19, 69, 0, 78, 9, 79, 0, 126, 0, 89, 0, 98, 0, 108, 29, 108, 0, 109, 0, 137, 0, 167, 9, 128, 0, 129, 0, 138, 39, 139, 0, 181, 0, 149, 0, 216, 0, 159, 19, 168, 9, 169, 49, 207, 0, 179, 0, 188, 0, 266, 0, 198, 0
OFFSET
1,2
FORMULA
a(n) = A284103(5*n-2).
G.f.: Sum_{k>0} (5*k-1) * x^(2*k) / (1 - x^(5*k-1)).
MATHEMATICA
a[n_] := DivisorSum[5*n - 2, # &, Mod[#, 5] == 4 &]; Array[a, 100] (* Amiram Eldar, Jul 17 2023 *)
PROG
(PARI) a(n) = sumdiv(5*n-2, d, (d%5==4)*d);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 04 2023
STATUS
approved