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 A089593 Numbers n such that n^2 + 2n + 2 is prime. 1

%I

%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 n such that n^2 + 2n + 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 (* _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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Last modified September 20 03:28 EDT 2020. Contains 337264 sequences. (Running on oeis4.)