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 A359238 Number of divisors of 5*n-4 of form 5*k+1. 7
 1, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 3, 4, 2, 2, 2, 2, 2, 4, 2, 2, 2, 4, 2, 4, 2, 2, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 2, 3, 2, 2, 2, 4, 2, 4, 2, 2, 2, 4, 2, 2, 2, 2, 2, 6, 4, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 6, 2, 2, 2, 4, 2, 4, 2, 2, 3, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Seiichi Manyama, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A001876(5*n-4). G.f.: Sum_{k>0} x^k/(1 - x^(5*k-4)). MATHEMATICA a[n_] := DivisorSum[5*n-4, 1 &, Mod[#, 5] == 1 &]; Array[a, 100] (* Amiram Eldar, Aug 23 2023 *) PROG (PARI) a(n) = sumdiv(5*n-4, d, d%5==1); (PARI) my(N=100, x='x+O('x^N)); Vec(sum(k=1, N, x^k/(1-x^(5*k-4)))) CROSSREFS Cf. A001876, A359233, A359236, A359237. Sequence in context: A096917 A336664 A335108 * A320011 A068049 A297850 Adjacent sequences: A359235 A359236 A359237 * A359239 A359240 A359241 KEYWORD nonn,easy AUTHOR Seiichi Manyama, Dec 22 2022 STATUS approved

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Last modified August 8 03:17 EDT 2024. Contains 375018 sequences. (Running on oeis4.)