A091199 Numbers k such that (6k-3)^2 + 2 is prime.
1, 2, 3, 4, 6, 7, 8, 10, 14, 17, 18, 19, 20, 21, 25, 29, 37, 38, 40, 41, 42, 43, 46, 50, 51, 52, 54, 58, 59, 61, 62, 63, 65, 70, 71, 72, 74, 75, 76, 80, 84, 86, 92, 93, 94, 96, 101, 102, 109, 113, 114, 117, 119, 126, 130, 135, 137, 140, 145, 148, 150, 151, 152, 156, 160
Offset: 1
Examples
10 is a member because (60-3)^2 + 2 = 3251 is prime.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Programs
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Magma
[n: n in [1..250]| IsPrime((6*n-3)^2+2)]; // Vincenzo Librandi, Jul 16 2012
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Mathematica
Select[ Range[ 163], PrimeQ[(6# - 3)^2 + 2] &] (* Robert G. Wilson v, Feb 26 2004 *) lst={};Do[If[PrimeQ[(6n-3)^2+2],AppendTo[lst,n]],{n,500}];lst (* Vincenzo Librandi, Jul 16 2012 *)
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PARI
is(n)=isprime((6*n-3)^2+2) \\ Charles R Greathouse IV, May 22 2017
Formula
a(n) = A056900(n-1) + 1. - Jeppe Stig Nielsen, May 14 2017
Extensions
More terms from Ray Chandler and Robert G. Wilson v, Feb 25 2004
Comments