OFFSET
1,1
COMMENTS
Subsequence of A142104.
Conjecture: except 2281, 2^a(n)-1 is not prime; in other words, these primes are included in A054723.
2*a(n) + 199 is a square. - Vincenzo Librandi, Apr 10 2015
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Table[2 n^2 + 30 n + 13, {n, 1000}], PrimeQ]
PROG
(Magma) [a: n in [1..800] | IsPrime(a) where a is 2*n^2+30*n+13];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jun 16 2014
STATUS
approved