A091271 Numbers k such that 4*k^2-11 is a prime.

2, 4, 5, 9, 10, 14, 16, 19, 21, 24, 26, 31, 35, 39, 40, 45, 59, 60, 65, 74, 79, 80, 86, 91, 100, 105, 109, 114, 115, 116, 119, 124, 126, 129, 130, 131, 135, 136, 145, 149, 150, 151, 159, 170, 171, 175, 179, 180, 185, 186, 189, 194, 199, 205, 206, 210, 219, 221

Offset: 1

Author

Ray Chandler, Dec 27 2003

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

A091272 gives primes, A091273 gives prime index.

Programs

GAP

Filtered([2..230],n->IsPrime(4*n^2-11)); # Muniru A Asiru, Jul 10 2018

Maple

select(t -> isprime(4*t^2-11), [$2..1000]); # Robert Israel, Jul 10 2018

PARI

is(n) = ispseudoprime(4*n^2-11) \\ Felix Fröhlich, Jul 10 2018

Formula

a(n) = A090696(n)/2.

Extensions

Offset changed by Robert Israel, Jul 10 2018