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 A101876 Number of Abelian groups of order 4n. 5
 2, 3, 2, 5, 2, 3, 2, 7, 4, 3, 2, 5, 2, 3, 2, 11, 2, 6, 2, 5, 2, 3, 2, 7, 4, 3, 6, 5, 2, 3, 2, 15, 2, 3, 2, 10, 2, 3, 2, 7, 2, 3, 2, 5, 4, 3, 2, 11, 4, 6, 2, 5, 2, 9, 2, 7, 2, 3, 2, 5, 2, 3, 4, 22, 2, 3, 2, 5, 2, 3, 2, 14, 2, 3, 4, 5, 2, 3, 2, 11, 10, 3, 2, 5, 2, 3, 2, 7, 2, 6, 2, 5, 2, 3, 2, 15, 2, 6, 4, 10, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 FORMULA a(n) = A000688(4*n). - Antti Karttunen, Sep 27 2018 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = (4 - 6 * A048651) * A021002 = 5.20306278505563943501... . - Amiram Eldar, Sep 23 2023 MATHEMATICA a[n_] := FiniteAbelianGroupCount[4*n]; Array[a, 100] (* Amiram Eldar, Sep 23 2023*) PROG (PARI) A101876(n) = factorback(apply(e -> numbpart(e), factor(4*n)[, 2])); \\ Antti Karttunen, Sep 27 2018 CROSSREFS Bisection of A101872, quadrisection of A000688. Cf. A000041, A021002, A048651. Sequence in context: A056927 A094290 A265111 * A260218 A087986 A129088 Adjacent sequences: A101873 A101874 A101875 * A101877 A101878 A101879 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Jan 28 2005 EXTENSIONS More terms from Joshua Zucker, May 10 2006 STATUS approved

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Last modified November 29 13:27 EST 2023. Contains 367445 sequences. (Running on oeis4.)