A081634 Class 6+ primes.

2917, 4933, 5413, 7507, 8167, 8753, 10567, 10627, 11047, 11261, 11677, 12073, 12251, 12421, 12433, 12553, 12721, 14293, 15017, 17041, 18181, 18493, 19267, 19333, 20023, 21193, 21313, 21661, 22397, 24481, 25933, 26261, 26437, 27361

Offset

1,1

References

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

Links

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

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[3000], ClassPlusNbr[ Prime[ # ]] == 6 &]]

Crossrefs

Cf. A005113, A005105, A005106, A005107, A005108, A081633, A081635, A081636, A081637, A081638, A081639.

Sequence in context: A209018 A186562 A157935 * A358879 A054830 A031552

Adjacent sequences: A081631 A081632 A081633 * A081635 A081636 A081637

Keyword

nonn

Author

Robert G. Wilson v, Mar 20 2003

Status

approved