A048524 Primes for which only two iterations of 'Prime plus its digit sum equals a prime' are possible.
11, 59, 101, 149, 167, 257, 293, 367, 419, 479, 547, 617, 727, 839, 1409, 1579, 1847, 2039, 2129, 2617, 2657, 2837, 3449, 3517, 3539, 3607, 3719, 4217, 4637, 4877, 5689, 5807, 5861, 6037, 6257, 6761, 7027, 7517, 8039, 8741, 8969, 9371, 9377, 10667
Offset: 1
Examples
prime 727 -> 727 + (7+2+7) = prime 743 -> 743 + (7+4+3) = prime 757 -> next iteration yields composite 776.
Links
- Lars Blomberg, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Select[Prime[Range[1400]],Boole[PrimeQ[Rest[NestList[ #+Total[ IntegerDigits[ #]]&,#,3]]]] == {1,1,0}&] (* Harvey P. Dale, Oct 31 2018 *)
Extensions
Changed offset by Lars Blomberg, Dec 05 2013