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 A212908 Numbers n such that A212813(n) = 3. 6
 13, 15, 16, 18, 19, 21, 22, 23, 25, 30, 32, 34, 36, 47, 53, 56, 63, 69, 74, 75, 76, 80, 90, 92, 96, 104, 108, 117, 123, 133, 136, 153, 165, 169, 172, 176, 190, 198, 228, 238, 245, 259, 273, 285, 286, 294, 304, 325, 328, 340, 342, 350, 357, 369, 370, 376, 385, 390, 403, 408, 416, 420, 423, 425, 429, 444, 448, 459, 462, 465, 468, 484, 496, 500 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES Bellamy, O. S.; Cadogan, C. C. Subsets of positive integers: their cardinality and maximality properties. Proceedings of the Tenth Southeastern Conference on Combinatorics, Graph Theory and Computing (Florida Atlantic Univ., Boca Raton, Fla., 1979), pp. 167--178, Congress. Numer., XXIII-XXIV, Utilitas Math., Winnipeg, Man., 1979. MR0561043 (82b:10006) LINKS Reinhard Zumkeller and Donovan Johnson, Table of n, a(n) for n = 1..2632 (terms up to a(2500) from Reinhard Zumkeller) MATHEMATICA nmax = 258280326 (* = last term = a(2632) *); kmax = 100 (* = number of terms to compute *); a36288[n_] := a36288[n] = If[n==1, 1, Total[Times @@@ FactorInteger[n]]+1]; a212813[n_] := Module[{i, k = n}, For[i = 1, i <= 4, i++, If[k == 8, Return[i-1]]; k = a36288[k]]; -1]; k = 0; Do[If[a212813[n] == 3, k++; If[k > kmax, Break[]]; a[k] = n; Print["a(", k, ") = ", n]], {n, 1, nmax}]; Array[a, kmax] (* Jean-François Alcover, Aug 02 2018 *) PROG (Haskell) import Data.List (elemIndices) a212908 n = a212908_list !! (n-1) a212908_list = map (+ 1) \$ elemIndices 3 a212813_list -- Reinhard Zumkeller, May 30 2012 CROSSREFS Cf. A212813, A212814, A212815, A212816, A212909. Sequence in context: A043657 A043702 A278978 * A180642 A176717 A070603 Adjacent sequences: A212905 A212906 A212907 * A212909 A212910 A212911 KEYWORD nonn,fini,full AUTHOR N. J. A. Sloane, May 30 2012 EXTENSIONS Keyword "full" added by Donovan Johnson, Jun 02 2012 STATUS approved

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Last modified September 10 00:26 EDT 2024. Contains 375769 sequences. (Running on oeis4.)