A168165 Primes which are the concatenation of a Sophie Germain prime p and 2p+1.

37, 1123, 2347, 113227, 173347, 281563, 359719, 431863, 491983, 5091019, 7191439, 11032207, 12292459, 15593119, 18893779, 19313863, 20394079, 23934787, 24594919, 34136827, 35397079, 37617523, 39117823, 43918783, 47939587

Offset

1,1

Comments

The corresponding primes p are listed in A168163.

A subsequence of A168166 (where p is not restricted to be a Sophie Germain prime).

Links

Table of n, a(n) for n=1..25.

Prog

(PARI) forprime(p=1, 9999, isprime(2*p+1) & isprime(eval(Str(p, 2*p+1))) & print1(p, 2*p+1, ", "))

Crossrefs

Sequence in context: A005390 A253245 A168166 * A340539 A219309 A099201

Adjacent sequences: A168162 A168163 A168164 * A168166 A168167 A168168

Keyword

base,nonn

Author

M. F. Hasler, Nov 25 2009

Status

approved