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 A363887 Number of divisors of 7*n-5 of form 7*k+3. 1
 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 1, 0, 2, 0, 0, 2, 0, 0, 2, 0, 2, 2, 0, 0, 2, 0, 0, 2, 0, 0, 4, 0, 0, 2, 0, 0, 2, 1, 0, 2, 2, 0, 2, 0, 0, 2, 0, 0, 2, 0, 2, 2, 0, 0, 4, 0, 0, 2, 0, 0, 4, 0, 0, 2, 0, 0, 2, 0, 0, 2, 2, 2, 2, 0, 0, 2, 0, 0, 3, 0, 2, 2, 0, 0, 2, 0, 0, 2, 2, 0, 4, 0, 0, 2, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Table of n, a(n) for n=1..100. FORMULA a(n) = A363805(7*n-5). G.f.: Sum_{k>0} x^(3*k-1)/(1 - x^(7*k-4)). MATHEMATICA a[n_] := DivisorSum[7*n - 5, 1 &, Mod[#, 7] == 3 &]; Array[a, 100] (* Amiram Eldar, Jun 26 2023 *) PROG (PARI) a(n) = sumdiv(7*n-5, d, d%7==3); CROSSREFS Cf. A363852, A363857, A363888. Cf. A363805. Sequence in context: A095808 A281453 A079807 * A341776 A116373 A341777 Adjacent sequences: A363884 A363885 A363886 * A363888 A363889 A363890 KEYWORD nonn AUTHOR Seiichi Manyama, Jun 26 2023 STATUS approved

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Last modified February 21 13:52 EST 2024. Contains 370235 sequences. (Running on oeis4.)