A171719 Numbers n such that 10^n*(8+3*10^n)+3 is prime.

1, 2, 4, 8, 17, 517, 581, 665, 890, 4901, 5230, 7515

Offset

1,2

Comments

Values corresponding to n=4901, n=5230, and n=7515 were all certified Fermat and Lucas PRPs with WinPFGW and the latter two (>10k digits) were submitted to Lifchitz's Top PRPs database. No more terms up to n=8100.

Links

Table of n, a(n) for n=1..12.

Prog

(PARI) is(n)=ispseudoprime(10^n*(8+3*10^n)+3) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A231435 A113153 A255999 * A185178 A351471 A229718

Adjacent sequences: A171716 A171717 A171718 * A171720 A171721 A171722

Keyword

more,nonn

Author

Jason Earls, Dec 16 2009

Status

approved