A118504 Sophie Germain primes whose sum of digits is also a Sophie Germain prime.

2, 3, 5, 11, 23, 29, 41, 83, 113, 131, 173, 191, 281, 443, 641, 911, 1013, 1019, 1031, 1103, 1451, 1499, 1811, 1901, 2003, 2063, 2351, 2399, 2939, 3299, 3389, 3413, 4793, 4919, 5051, 5231, 5279, 5303, 5501, 5639, 6113, 6131, 6269, 6449, 7079, 7103, 7121, 7211

Offset: 1

Author

Luc Stevens (lms022(AT)yahoo.com), May 06 2006; corrected May 12 2006

Keywords

• base
• nonn

Examples

			191 is in the sequence because it is a Sophie Germain prime and the sum of its digits 1+9+1 = 11 is also a Sophie Germain prime.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harvey P. Dale)

Crossrefs

Subsequence of A118571.

Cf. A005384.

Programs

Mathematica

sgpQ[n_]:=Module[{c=Total[IntegerDigits[n]]},And@@PrimeQ[{2n+1,c,2c+1}]]; Select[Prime[Range[1000]],sgpQ] (* Harvey P. Dale, Oct 14 2012 *)

Extensions

Corrected by T. D. Noe, Oct 25 2006

Corrected by Harvey P. Dale, Oct 14 2012