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A081424
Class 5- primes (for definition see A005109).
12
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
OFFSET
1,1
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, A18.
LINKS
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 &]]
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Mar 20 2003
STATUS
approved