OFFSET
1,2
COMMENTS
The sum of the reciprocals of the primes generated from these indices converges to 0.2332142.. The sum of the reciprocals of these indices cannot be computed.
All terms are divisible by 6. - Zak Seidov, Dec 27 2014
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Near-Square Prime
FORMULA
a(n) = 6 * A056906(n).
MATHEMATICA
Select[Range[0, 1000], PrimeQ[#^2+5]&] (* Vincenzo Librandi, Jul 13 2012 *)
PROG
(PARI) for(n=0, 10^4, q=n^2+5; if(isprime(q), print1(n, ", ")));
(Magma) [n: n in [0..1000]| IsPrime(n^2+5)]; // Vincenzo Librandi, Jul 15 2012
CROSSREFS
KEYWORD
nonn,easy,changed
AUTHOR
Cino Hilliard, Dec 26 2002
EXTENSIONS
Offset corrected by Arkadiusz Wesolowski, Aug 09 2011
STATUS
approved