A102657 Numbers k such that 11*k^2 + 11*k + 1 is prime.

1, 2, 5, 6, 7, 9, 11, 13, 14, 20, 23, 25, 26, 27, 28, 32, 33, 36, 37, 40, 42, 48, 49, 50, 51, 58, 61, 62, 68, 74, 75, 76, 77, 78, 81, 84, 92, 96, 103, 104, 109, 111, 119, 120, 126, 127, 133, 135, 137, 141, 142, 144, 145, 149, 153, 156, 158, 163, 166, 168, 169, 172, 176

Offset

1,2

Links

Table of n, a(n) for n=1..63.

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

Sequence in context: A047580 A153384 A369962 * A202115 A047324 A327184

Adjacent sequences: A102654 A102655 A102656 * A102658 A102659 A102660

Keyword

nonn,easy

Author

Parthasarathy Nambi, Feb 02 2005

Status

approved