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A363854
Number of divisors of 7*n-2 of form 7*k+6.
5
0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 1, 1, 0, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 2, 0, 2, 0, 1, 1, 1, 0, 2, 0, 1, 0, 1, 1, 3, 0, 2, 0, 1, 0, 2, 0, 1, 1, 1, 0, 3, 0, 1, 0, 1, 0, 4, 0, 1, 0, 2, 0, 2, 1, 1, 1, 1, 0, 2, 0, 1, 0, 2, 0, 3, 0, 2, 0, 1, 0, 3, 0, 1, 2, 1, 0, 2, 0, 2, 1, 1, 0, 3, 0, 1
OFFSET
1,8
COMMENTS
Also number of divisors of 7*n-2 of form 7*k+2.
FORMULA
a(n) = A363795(7*n-2) = A363808(7*n-2).
G.f.: Sum_{k>0} x^(2*k)/(1 - x^(7*k-1)).
G.f.: Sum_{k>0} x^(6*k-4)/(1 - x^(7*k-5)).
MATHEMATICA
a[n_] := DivisorSum[7*n - 2, 1 &, Mod[#, 7] == 6 &]; Array[a, 100] (* Amiram Eldar, Jun 25 2023 *)
PROG
(PARI) a(n) = sumdiv(7*n-2, d, d%7==6);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 24 2023
STATUS
approved