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A363886
Number of divisors of 7*n-3 of form 7*k+5.
1
0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 1, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 2, 0, 0, 0, 2, 0, 0, 1, 0, 2, 0, 0, 2, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 4, 0, 2, 0, 0, 2, 0, 0, 0, 0, 2, 0, 2, 0, 0, 2, 0, 0, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 1, 0, 2, 0
OFFSET
1,9
FORMULA
a(n) = A363807(7*n-3).
G.f.: Sum_{k>0} x^(5*k-1)/(1 - x^(7*k-2)).
MATHEMATICA
a[n_] := DivisorSum[7*n - 3, 1 &, Mod[#, 7] == 5 &]; Array[a, 100] (* Amiram Eldar, Jun 26 2023 *)
PROG
(PARI) a(n) = sumdiv(7*n-3, d, d%7==5);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 26 2023
STATUS
approved