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%I #21 Sep 08 2022 08:45:12
%S 0,1,3,5,9,13,15,19,23,25,35,39,53,55,65,73,83,89,93,109,115,119,123,
%T 125,129,133,145,149,155,159,169,175,179,183,203,205,209,223,229,235,
%U 239,249,255,259,263,269,279,283,299,305,313,325,339,349
%N Numbers k such that k^2 + 2k + 2 is prime.
%D M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
%D Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997
%H Vincenzo Librandi, <a href="/A089593/b089593.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = A005574(n)-1 = A090693(n)-2.
%t Select[Range[0,1000],PrimeQ[#^2+2#+2]&] (* _Vincenzo Librandi_, May 23 2014 *)
%o (Magma)[n: n in [0..400]|IsPrime(n^2+2*n+2)]; // _Vincenzo Librandi_, Dec 17 2010
%o (PARI) is(n)=isprime(n^2+2*n+2) \\ _Charles R Greathouse IV_, Jun 12 2017
%Y Cf. A002496 gives the primes, A005574, A090693.
%K nonn,easy
%O 1,3
%A _Giovanni Teofilatto_, Dec 30 2003
%E Corrected by _Vincenzo Librandi_, Dec 17 2010
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