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 A081424 Class 5- primes (for definition see A005109). 15
 283, 359, 557, 659, 941, 1109, 1129, 1223, 1433, 1663, 1669, 1693, 1787, 1997, 2027, 2039, 2069, 2083, 2153, 2339, 2351, 2503, 2539, 2579, 2633, 2767, 2777, 2803, 2837, 2999, 3229, 3581, 3761, 3767, 3779, 3989, 4127, 4157, 4231, 4253, 4283, 4297, 4513 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES R. K. Guy, Unsolved Problems in Number Theory, A18. 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[700], ClassMinusNbr[ Prime[ # ]] == 5 &]] CROSSREFS Cf. A005113, A056637, A005109, A005110, A005111, A005112, A081425, A081426, A081427, A081428, A081429, A081430. Sequence in context: A175276 A334096 A142937 * A142699 A113157 A142446 Adjacent sequences:  A081421 A081422 A081423 * A081425 A081426 A081427 KEYWORD nonn AUTHOR Robert G. Wilson v, Mar 20 2003 STATUS approved

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Last modified September 19 16:34 EDT 2021. Contains 347564 sequences. (Running on oeis4.)