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 A328043 Number of divisors of the amicable pairs. 6
 12, 6, 12, 12, 12, 12, 12, 12, 16, 12, 16, 16, 32, 16, 20, 10, 24, 12, 20, 20, 32, 32, 48, 24, 32, 16, 48, 24, 48, 24, 20, 20, 24, 16, 32, 16, 20, 20, 20, 20, 32, 16, 24, 24, 36, 12, 24, 12, 48, 16, 32, 16, 20, 20, 18, 36, 20, 20, 48, 48, 32, 16, 32, 16, 32, 16, 32, 16, 32, 16, 48, 24, 32, 16, 48, 32, 24, 20 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Amiram Eldar, Table of n, a(n) for n = 1..20000 FORMULA a(n) = A000005(A259180(n)). EXAMPLE Consider the first amicable pair [220, 284]. The smaller member has 12 divisors, they are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110, 220. The larger member has 6 divisors, they are 1, 2, 4, 71, 142, 284. So a(1) = 12 and a(2) = 6. MATHEMATICA With[{s = Array[{#, DivisorSigma[1, #] - #} &, 10^5]}, DivisorSigma[0, #] &@ Flatten@ DeleteDuplicates[Sort /@ Select[Reverse /@ s, And[! FreeQ[s, #], UnsameQ @@ #] &]]] (* Michael De Vlieger, Oct 08 2019 *) CROSSREFS Row lengths of A328009. Cf. A000005, A259180, A328063, A328064, A328065. Sequence in context: A084067 A240537 A227354 * A075247 A257841 A173853 Adjacent sequences:  A328040 A328041 A328042 * A328044 A328045 A328046 KEYWORD nonn AUTHOR Omar E. Pol, Oct 02 2019 STATUS approved

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Last modified March 30 05:01 EDT 2020. Contains 333118 sequences. (Running on oeis4.)