OFFSET
0,3
COMMENTS
36m^2+36m+11=(6m+3)^2+2, i.e. two more than the square of odd multiples of 3. 36m^2+36m+11=72*(m*(m+1)/2)+11, i.e. eleven more than seventy-two times triangular numbers.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A091199(n+1) - 1. - Jeppe Stig Nielsen, May 14 2017
EXAMPLE
a(3)=3 because 36*3^2+36*3+11=443 which is prime
MATHEMATICA
lst={}; Do[If[PrimeQ[36*n^2+36*n+11], AppendTo[lst, n]], {n, 0, 100}]; lst (* Vincenzo Librandi, Jul 14 2012 *)
Select[Range[0, 200], PrimeQ[36#^2+36#+11]&] (* Harvey P. Dale, Sep 19 2020 *)
PROG
(Magma) [n: n in [0..200]| IsPrime(36*n^2+36*n+11)]; // Vincenzo Librandi, Jul 14 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Henry Bottomley, Jul 05 2000
STATUS
approved