A174180 Numbers n>0 such that 10^n+2^n+1 is prime.

1, 3, 9, 17, 19, 27, 351, 813, 869, 1387

Offset

1,2

Comments

Terms greater than 351 yield probable primes. Next term > 10000. - Vaclav Kotesovec, Apr 30 2014

Links

Table of n, a(n) for n=1..10.

Mathematica

Select[Range[1, 1000], PrimeQ[10^#+2^#+1]&] (* Vaclav Kotesovec, Apr 30 2014 *)

Prog

(Magma) [n: n in [1..800] | IsPrime(10^n+2^n+1) ]

Crossrefs

Sequence in context: A056403 A181349 A240094 * A106676 A050795 A050797

Adjacent sequences: A174177 A174178 A174179 * A174181 A174182 A174183

Keyword

nonn,more

Author

Vincenzo Librandi, Mar 11 2010

Extensions

a(8)-a(10) from Vaclav Kotesovec, Apr 30 2014

Status

approved