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%I #12 Jan 04 2018 02:47:26
%S 3,5,6,12,14,17,20,21,27,54,57,66,69,71,77,90,101,131,141,150,155,161,
%T 164,189,192,194,231,245,266,332,336,344,351,381,392,402,434,456,476,
%U 495,500,512,531,551,572,579,582,605,626,671,677,696,747,755,762,782,839
%N Numbers n such that n*(n-1)-1 and n*(n+1)+1 are both primes.
%H Robert Israel, <a href="/A100712/b100712.txt">Table of n, a(n) for n = 1..10000</a>
%p select(n -> isprime(n*(n-1)-1) and isprime(n*(n+1)+1),[$1..1000]); # _Robert Israel_, Jan 04 2018
%t Select[Range[6! ],PrimeQ[ #^2-(#+1)]&&PrimeQ[ #^2+(#+1)]&] (* _Vladimir Joseph Stephan Orlovsky_, Dec 19 2009 *)
%K easy,nonn
%O 1,1
%A _Pierre CAMI_, Dec 10 2004
%E a(54)=755 inserted by _Robert Israel_, Jan 04 2018
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