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A005112
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Class 4- primes (for definition see A005109).
(Formerly M5289)
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13
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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
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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.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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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[300], ClassMinusNbr[ Prime[ # ]] == 4 &]]
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CROSSREFS
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Cf. A005113, A056637, A005109, A005110, A005111, A081424, A081425, A081426, A081427, A081428, A081429, A081430
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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