This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A089747 #21 Sep 08 2022 08:45:12 %S A089747 0,2,4,6,8,14,16,18,28,34,36,38,46,48,58,66,68,74,86,88,96,98,104,116, %T A089747 118,126,136,138,148,156,164,168,178,184,194,204,208,216,218,234,236, %U A089747 244,246,254,256,266,268,276,278,288,294,304,308,314,318,348,358,374 %N A089747 Numbers n such that n^2 - 2n + 5 is prime. %D A089747 M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna, 1988. %D A089747 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano, 1997. %F A089747 a(n) = A007591(n-1) + 1 for n > 1. [corrected by _Georg Fischer_, Jun 20 2020] %t A089747 Select[Range[0,400,2],PrimeQ[#^2-2#+5]&] (* _Harvey P. Dale_, Jan 04 2015 *) %o A089747 (Magma) [n: n in [0..100]|IsPrime(n^2-2*n+5)] // _Vincenzo Librandi_, Nov 16 2010 %o A089747 (PARI) is(n)=isprime(n^2-2*n+5) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A089747 Cf. A005473 gives primes, A007591. %K A089747 nonn,easy %O A089747 1,2 %A A089747 _Giovanni Teofilatto_, Jan 08 2004