A090468 Class 13+ primes.

545587687, 852480757, 1048438561, 1150849009, 1323457987, 1745980517, 1756123441, 1785398401, 1798736161, 1892507347, 1937020021, 2002155601, 2136716521, 2150905573, 2229004913, 2548101601, 2671514917, 2838761021

Offset: 1

Author

Robert G. Wilson v, Nov 26 2003

Keywords

• nonn

References

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

Links

• M. F. Hasler, Table of n, a(n) for n=1..850

Crossrefs

Cf. A005113, A005105 - A005108, A081633 - A081639, A084071, A129474.

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[195000000], ClassPlusNbr[ Prime[ # ]] == 13 &]]