%I #23 Mar 21 2019 07:10:33
%S -65,145,259,-311,-635,679,-1001,1099,-1109,-1475,1549,-1571,1885,
%T 1969,-1991,2125,-2165,2191,2431,-3005,-3269,3451,-3719,-3941,-4265,
%U 4975,5359,5731,-5861,6109,-6221,-6359,6409,6529,-6695,-6851,7105,7525,7681,7879,-8165,8365,-8711,9109,-9221,-9299,-9305,9349,-9761,9835,9919
%N Values of n such that L(6) and N(6) are both prime, where L(k) = (n^2+n+1)*2^(2*k) + (2*n+1)*2^k + 1, N(k) = (n^2+n+1)*2^k + n.
%C Computed with PARI using commands similar to those used to compute A226921.
%H Vincenzo Librandi and Joerg Arndt, <a href="/A226926/b226926.txt">Table of n, a(n) for n = 1..1000</a>
%H Eric L. F. Roettger, <a href="http://people.ucalgary.ca/~hwilliam/files/A_Cubic_Extention_of_the_Lucas_Functions.pdf">A cubic extension of the Lucas functions</a>, Thesis, Dept. of Mathematics and Statistics, Univ. of Calgary, 2009. See page 195.
%t k = 6; (* adjust for related sequences *) fL[n_] := (n^2 + n + 1)*2^(2*k) + (2*n + 1)*2^k + 1; fN[n_] := (n^2 + n + 1)*2^k + n; nn = 10000; A = {}; For[n = -nn, n <= nn, n++, If[PrimeQ[fL[n]] && PrimeQ[fN[n]], AppendTo[A, n]]]; cmpfunc[x_, y_] := If[x == y, Return[True], ax = Abs[x]; ay = Abs[y]; If[ax == ay, Return[x < y], Return[ ax < ay]]]; Sort[A, cmpfunc] (* _Jean-François Alcover_, Jul 17 2013, translated and adapted from Joerg Arndt's Pari program in A226921 *)
%Y Cf. A226921-A226929, A227448, A227449, A227515-A227523.
%K sign
%O 1,1
%A _N. J. A. Sloane_, Jul 12 2013
%E More terms from _Vincenzo Librandi_, Jul 13 2013