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Search: id:A081641
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| A081641 |
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a(n) = n-th prime of class 13- according to the Erdos-Selfridge classification. |
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+0
6
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| 36449279, 53065907, 59681213, 69096887, 132756479, 135388367, 164255999, 179043637, 188991053, 207290663, 241560239, 279709259, 309550999, 364492781, 372993983, 377982103, 398007431, 406165099, 425633717, 445901987, 447609067, 516737983
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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R. K. Guy, Unsolved Problems in Number Theory, A18.
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LINKS
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M. F. Hasler, Table of n, a(n) for n=1..1641
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MATHEMATICA
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PrimeFactors[n_Integer] := Flatten[ Table[ #[[1]], {1}] & /@ FactorInteger[n]]; f[n_Integer] := Block[{m = n}, If[m == 0, m = 1, While[ IntegerQ[m/2], m /= 2]; While[ IntegerQ[m/3], m /= 3]]; Apply[Times, PrimeFactors[m] - 1]]; ClassMinusNbr[n_] := Length[ NestWhileList[f, n, UnsameQ, All]] - 3; Prime[ Select[ Range[23733333], ClassMinusNbr[ Prime[ # ]] == 12 &]]
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PROGRAM
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(PARI) A081641 = nextclassminus(A081640) /* cf. A081640 */ - M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Apr 05 2007
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CROSSREFS
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Cf. A005113, A005105, A005106, A005107, A005108, A081633, A081633, A081635, A081636, A081637, A081638.
Cf. A056637, A081640, A129248.
Sequence in context: A037252 A064586 A105296 this_sequence A028965 A034645 A015365
Adjacent sequences: A081638 A081639 A081640 this_sequence A081642 A081643 A081644
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 23 2003
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), May 14 2008 at the suggestion of R. J. Mathar.
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