A085555 Primes p of the form x^2+4, such that either p-2 or p+2 is prime.

5, 13, 29, 229, 1093, 1229, 2029, 3253, 4229, 13693, 21613, 59053, 65029, 91813, 140629, 178933, 199813, 205213, 227533, 328333, 366029, 567013, 700573, 804613, 815413, 819029, 1071229, 1155629, 1311029, 1575029, 2241013, 3629029, 3822029

Offset

1,1

Links

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

Maple

select(t -> isprime(t) and (isprime(t+2) or isprime(t-2)), [seq(x^2+4, x=1..10^4, 2)]); # Robert Israel, May 14 2018

Mathematica

okQ[n_]:=PrimeQ[n]&&(PrimeQ[n-2]||PrimeQ[n+2]); Select[Range[ 2000]^2+4, okQ] (* Harvey P. Dale, Jul 14 2011 *)

Crossrefs

Sequence in context: A381017 A147492 A182069 * A224888 A256314 A002768

Adjacent sequences: A085552 A085553 A085554 * A085556 A085557 A085558

Keyword

easy,nonn

Author

Cino Hilliard, Jul 04 2003

Extensions

Edited by Don Reble, May 03 2006

Status

approved