OFFSET
1,2
EXAMPLE
For k=1, 11*k^2 + 11*k + 1 = 11*1^2 + 11*1 + 1 = 23 (prime).
For k=20, 11*k^2 + 11*k + 1 = 11*20^2 + 11*20 + 1 = 4621 (prime).
For k=40, 11*k^2 + 11*k + 1 = 11*40^2 + 11*40 + 1 = 18041 (prime).
MATHEMATICA
Select[Range[200], PrimeQ[11#^2+11#+1]&] (* Harvey P. Dale, Aug 15 2012 *)
PROG
(Magma) [n: n in [0..1000] | IsPrime(11*n^2+11*n+1)]; // Vincenzo Librandi, Nov 17 2010
(PARI) is(n)=isprime(11*n^2+11*n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Parthasarathy Nambi, Feb 02 2005
STATUS
approved