OFFSET
1,1
COMMENTS
a(n) is congruent to 1 (mod 4).
Primes of the form 2*k^2 + 10*k + 5 or 2*k^2 - 6*k - 3. - Vincenzo Librandi, Apr 19 2010
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Table[5n^2-3(n+1)^2, {n, 4, 200}], PrimeQ] (* Harvey P. Dale, Aug 07 2017 *)
PROG
(Magma) [ p: p in PrimesUpTo(60000) | exists(t){ n: n in [1..Isqrt(p)] | p eq 5*n^2-3*(n-1)^2 } ]; //y = x-1
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Teofilatto, Apr 18 2010
EXTENSIONS
Comment corrected by Giovanni Teofilatto, Apr 19 2010
STATUS
approved