A050769 Iterated procedure 'composite k added to sum of its prime factors reaches a prime' yields 2 skipped primes.

10, 12, 14, 15, 21, 44, 90, 135, 210, 252, 294, 384, 468, 504, 513, 686, 704, 720, 768, 832, 864, 972, 1155, 1368, 1701, 1890, 2176, 2184, 2352, 2400, 2880, 3080, 3400, 3640, 3888, 4032, 4536, 4725, 5200, 6174, 6384, 8750, 9548, 10350, 10400, 10500

Offset: 0

Author

Patrick De Geest, Sep 15 1999

Keywords

• nonn

Examples

			a(6) = 44 + (2 + 2 + 11) = ending prime 59. Between 44 and 59 there are 2 primes: 47 and 53.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..333 (all terms up to 5*10^6)

Crossrefs

Cf. A050703, A050710.

Programs

Mathematica

ckpgQ[n_]:=Module[{c=n+Total[Flatten[Table[#[[1]],{#[[2]]}]&/@ FactorInteger[ n]]]},CompositeQ[n]&&PrimeQ[c]&&PrimePi[c]-PrimePi[n] == 3]; Select[Range[11000],ckpgQ] (* Harvey P. Dale, Nov 29 2014 *)