A081635 Class 7+ primes.

15013, 16333, 22093, 24841, 43321, 49003, 52517, 54721, 62533, 63761, 69061, 69073, 70061, 74597, 75781, 75793, 75913, 82561, 83233, 84673, 87433, 87509, 88793, 91081, 92761, 94321, 98737, 99367, 101641, 105097, 110881, 111973, 114343

Offset: 1

Author

Robert G. Wilson v, Mar 20 2003

Keywords

• nonn

References

• R. K. Guy, Unsolved Problems in Number Theory, A18.

Links

• T. D. Noe, Table of n, a(n) for n=1..10000

Crossrefs

Cf. A005113, A005105, A005106, A005107, A005108, A081633, A081634, A081636, A081637, A081638, A081639.

Programs

Maple

For Maple program see Mathar link in A005105.

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]]; ClassPlusNbr[n_] := Length[ NestWhileList[f, n, UnsameQ, All]] - 3; Prime[ Select[ Range[10820], ClassPlusNbr[ Prime[ # ]] == 7 &]]