OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
19 is in this sequence because 4*19^2 + 4*19 + 653 = 2173 = 41*53.
MATHEMATICA
Select[Range[0, 250], ! PrimeQ[4 #^2 + 4 # + 653] &]
PROG
(Magma) [n: n in [0..250] | not IsPrime(4*n^2+4*n+653)];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 20 2014
STATUS
approved