A171655 Numbers n such that 10^n*(7+3*10^n)+3 is prime.

0, 1, 2, 3, 7, 20, 22, 65, 122, 355, 561, 2216, 5638, 7271

Offset

1,3

Comments

Values corresponding to n=5638 and n=7271 were both certified Fermat and Lucas PRPs with WinPFGW and submitted to Lifchitz's Top PRPs database.

Links

Table of n, a(n) for n=1..14.

Prog

(PARI) is(n)=ispseudoprime(10^n*(7+3*10^n)+3) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A110498 A244917 A172976 * A293683 A006073 A052402

Adjacent sequences: A171652 A171653 A171654 * A171656 A171657 A171658

Keyword

more,nonn

Author

Jason Earls, Dec 14 2009

Status

approved