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Numbers n such that 8n^2 + 6n + 3 is prime.
3

%I #13 May 22 2017 11:50:34

%S 0,1,2,5,8,10,13,17,20,22,23,25,31,32,37,38,40,41,43,46,47,55,61,70,

%T 80,82,85,88,91,100,101,106,107,110,112,116,118,125,131,148,151,152,

%U 155,160,161,163,166,172,173,176,196,200,202,211,212,223,226,227,245,247

%N Numbers n such that 8n^2 + 6n + 3 is prime.

%F a(n) = A096689(n)/2.

%t f[n_]:=n^2+(n+1)^2+(n+2); lst={};Do[p=f[n];If[PrimeQ[p],AppendTo[lst,n/2]],{n,0,6!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Jul 04 2009 *)

%t Select[Range[0,300],PrimeQ[8#^2+6#+3]&] (* _Harvey P. Dale_, Jun 11 2015 *)

%o (PARI) is(n)=isprime(8*n^2+6*n+3) \\ _Charles R Greathouse IV_, May 22 2017

%Y Cf. A095697, A096689, A096690.

%K nonn

%O 1,3

%A _Ray Chandler_, Jul 12 2004