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 A256259 Sum of divisors of the minimal numbers (A007416). 1
 1, 3, 7, 12, 28, 31, 60, 91, 124, 168, 127, 360, 403, 546, 508, 744, 1170, 1651, 2418, 2880, 2821, 3048, 2047, 4368, 3751, 5952, 9360, 9906, 8188, 12493, 8191, 19344, 15367, 22568, 22506, 24384, 28800, 26611, 39312, 32764, 51181, 59520, 49128, 79248, 99944, 92202, 112320, 116281, 106483, 160797 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Has a symmetric representation in the same way as A000203 and all its subsequences. LINKS FORMULA a(n) = A000203(A007416(n)). MATHEMATICA (* The d-th element in list minDiv[n, b] is the smallest numbers k<=n with exactly d<=b divisors, otherwise it is zero. Computation stops as soon as either inequality fails. *) minDiv[n_, b_] := Module[{list = Array[0 &, b], k = 1, d},   While[k <= n, d = DivisorSigma[0, k];    If[d <= b && list[[d]] == 0, list[[d]] = k];    If[d <= b, k++, k = n + 2]]; list] a256259[n_, b_] := Map[DivisorSigma[1, #] &, Sort[Select[minDiv[n, b], # != 0 &]]] a256259[100000, 300] (* computes the first 60 elements of the sequence *) (*Hartmut F. W. Hoft, Apr 27 2015 *) CROSSREFS Cf. A000203, A005179, A007416, A007626, A053212, A063072, A081533, A237271. Sequence in context: A196858 A099811 A196917 * A182941 A063072 A007626 Adjacent sequences:  A256256 A256257 A256258 * A256260 A256261 A256262 KEYWORD nonn AUTHOR Omar E. Pol, Apr 20 2015 STATUS approved

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Last modified October 20 12:47 EDT 2019. Contains 328257 sequences. (Running on oeis4.)