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A364093
Sum of divisors of 5*n-2 of form 5*k+1.
4
1, 1, 1, 7, 1, 1, 12, 1, 1, 23, 1, 1, 22, 1, 1, 33, 1, 12, 32, 1, 1, 43, 1, 1, 42, 17, 1, 53, 12, 1, 52, 1, 1, 84, 1, 1, 62, 1, 1, 84, 1, 43, 72, 1, 1, 83, 1, 1, 82, 32, 12, 93, 1, 1, 113, 1, 1, 155, 1, 1, 102, 12, 1, 113, 1, 42, 112, 27, 1, 123, 1, 1, 133, 63, 1, 154, 1, 1, 132, 1, 32, 194, 1, 12, 142
OFFSET
1,4
FORMULA
a(n) = A284097(5*n-2).
G.f.: Sum_{k>0} (5*k-4) * x^(3*k-2) / (1 - x^(5*k-4)).
MATHEMATICA
a[n_] := DivisorSum[5*n - 2, # &, Mod[#, 5] == 1 &]; Array[a, 100] (* Amiram Eldar, Jul 17 2023 *)
PROG
(PARI) a(n) = sumdiv(5*n-2, d, (d%5==1)*d);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 04 2023
STATUS
approved