A081425 Class 6- primes (for definition see A005109).

719, 1319, 1699, 2447, 3343, 4079, 4139, 4457, 4517, 4679, 4703, 5273, 5647, 6653, 6793, 7523, 7529, 7559, 8599, 9227, 9587, 9623, 9839, 10159, 10343, 10723, 10771, 11069, 11213, 11279, 11321, 11489, 11863, 11887, 12163, 12917, 12919, 13163

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[1700], ClassMinusNbr[ Prime[ # ]] == 6 &]]

Crossrefs

Cf. A005113, A056637, A005109, A005110, A005111, A005112, A081424, A081426, A081427, A081428, A081429, A081430.

Sequence in context: A252528 A351669 A361345 * A101797 A144767 A127227

Adjacent sequences: A081422 A081423 A081424 * A081426 A081427 A081428

Keyword

nonn

Author

Robert G. Wilson v, Mar 20 2003

Status

approved