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A050769
Iterated procedure 'composite k added to sum of its prime factors reaches a prime' yields 2 skipped primes.
1
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
0,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..333 (all terms up to 5*10^6)
EXAMPLE
a(6) = 44 + (2 + 2 + 11) = ending prime 59. Between 44 and 59 there are 2 primes: 47 and 53.
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 *)
CROSSREFS
Sequence in context: A050705 A095406 A337028 * A330724 A351998 A088381
KEYWORD
nonn
AUTHOR
Patrick De Geest, Sep 15 1999
STATUS
approved