A081428 Class 9- primes.

34549, 86371, 103613, 120919, 138059, 149519, 172583, 172741, 224563, 276293, 282059, 282143, 293659, 299417, 316691, 352399, 368513, 379903, 397303, 403061, 414577, 451499, 483179, 486527, 489431, 500947, 506537, 517747, 518047, 541799

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..6505

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[50000], ClassMinusNbr[ Prime[ # ]] == 9 &]]

Crossrefs

Cf. A005113, A056637, A005109, A005110, A005111, A005112, A081424, A081425, A081426, A081427, A081429, A081430.

Sequence in context: A344780 A068703 A225025 * A237955 A023336 A172579

Adjacent sequences: A081425 A081426 A081427 * A081429 A081430 A081431

Keyword

nonn

Author

Robert G. Wilson v, Mar 20 2003

Status

approved