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 A005111 Class 3- primes (for definition see A005109). (Formerly M5133) 15
 23, 59, 67, 83, 89, 107, 173, 199, 227, 233, 263, 311, 317, 331, 349, 353, 367, 373, 383, 397, 419, 431, 463, 479, 503, 509, 523, 563, 569, 587, 607, 617, 619, 661, 683, 727, 733, 739, 743, 787, 809, 821, 823, 853, 859, 881, 887, 907, 929, 947, 977, 983, 991, 1031, 1033 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES R. K. Guy, Unsolved Problems in Number Theory, A18. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS R. J. Mathar, Table of n, a(n) for n = 1..20000 MATHEMATICA 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[175], ClassMinusNbr[ Prime[ # ]] == 3 &]] CROSSREFS Cf. A005113, A056637, A005109, A005110, A005112, A081424, A081425, A081426, A081427, A081428, A081429, A081430. Sequence in context: A039346 A043169 A043949 * A225550 A179629 A274381 Adjacent sequences: A005108 A005109 A005110 * A005112 A005113 A005114 KEYWORD nonn AUTHOR N. J. A. Sloane, Simon Plouffe EXTENSIONS Edited and extended by Robert G. Wilson v, Mar 20 2003 Corrected by R. J. Mathar, Feb 01 2007 STATUS approved

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Last modified September 25 15:05 EDT 2023. Contains 365648 sequences. (Running on oeis4.)