A188574 Numbers n such that n^2 + 2*n + 2^n is prime.

1, 3, 5, 7, 13, 15, 35, 43, 159, 245, 265, 1573, 1827, 3359, 3949, 4615, 5463, 5919, 19723

Offset: 1

Author

Vincenzo Librandi, Jan 07 2013

Keywords

• nonn

Crossrefs

Cf. A220425 (see the comment by Jonathan Vos Post).

Programs

Mathematica

Select[Range[1, 10000, 2], PrimeQ[#^2 + 2 # + 2^#] &]

PARI

is(n)=ispseudoprime(n^2+2*n+2^n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(19) from Bruno Berselli, Jan 09 2013