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A363877
Number of divisors of 7*n-2 of form 7*k+3.
0
0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 2, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 3, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 3, 0, 0, 1, 1, 0, 2, 0, 2, 1, 0, 1, 2, 0, 0, 1, 1, 0, 2, 0, 1, 1, 1, 1, 3, 0, 0, 1, 2, 0, 1, 0, 1, 2, 0, 0, 2, 0, 1, 1, 2, 0, 2, 0, 2, 1, 0, 0, 4, 0, 0, 1, 1, 0, 1, 1, 1, 2, 1, 0, 3, 0, 0
OFFSET
1,14
COMMENTS
Also number of divisors of 7*n-2 of form 7*k+4.
FORMULA
a(n) = A363805(7*n-2) = A363806(7*n-2).
G.f.: Sum_{k>0} x^(4*k-2)/(1 - x^(7*k-4)).
G.f.: Sum_{k>0} x^(3*k-1)/(1 - x^(7*k-3)).
MATHEMATICA
a[n_] := DivisorSum[7*n - 2, 1 &, Mod[#, 7] == 3 &]; Array[a, 100] (* Amiram Eldar, Jun 25 2023 *)
PROG
(PARI) a(n) = sumdiv(7*n-2, d, d%7==3);
CROSSREFS
Sequence in context: A362983 A352822 A090418 * A322452 A076754 A346482
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 25 2023
STATUS
approved