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 A005112 Class 4- primes (for definition see A005109). (Formerly M5289) 15
 47, 139, 167, 179, 269, 277, 347, 461, 467, 499, 599, 643, 691, 709, 797, 827, 829, 839, 857, 863, 967, 997, 1013, 1019, 1039, 1063, 1069, 1151, 1163, 1181, 1289, 1367, 1381, 1399, 1427, 1487, 1493, 1499, 1579, 1609, 1619, 1657, 1867, 1877, 1889, 1933, 1979 (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[300], ClassMinusNbr[ Prime[ # ]] == 4 &]] CROSSREFS Cf. A005113, A056637, A005109, A005110, A005111, A081424, A081425, A081426, A081427, A081428, A081429, A081430 Sequence in context: A039530 A288408 A095311 * A355727 A062637 A212374 Adjacent sequences:  A005109 A005110 A005111 * A005113 A005114 A005115 KEYWORD nonn AUTHOR EXTENSIONS Edited and extended by Robert G. Wilson v, Mar 20 2003 STATUS approved

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Last modified November 26 05:48 EST 2022. Contains 358353 sequences. (Running on oeis4.)