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 A089747 Numbers n such that n^2 - 2n + 5 is prime. 0
 0, 2, 4, 6, 8, 14, 16, 18, 28, 34, 36, 38, 46, 48, 58, 66, 68, 74, 86, 88, 96, 98, 104, 116, 118, 126, 136, 138, 148, 156, 164, 168, 178, 184, 194, 204, 208, 216, 218, 234, 236, 244, 246, 254, 256, 266, 268, 276, 278, 288, 294, 304, 308, 314, 318, 348, 358, 374 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna, 1988. Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano, 1997. LINKS FORMULA a(n) = A007591(n-1) + 1 for n > 1. [corrected by Georg Fischer, Jun 20 2020] MATHEMATICA Select[Range[0, 400, 2], PrimeQ[#^2-2#+5]&] (* Harvey P. Dale, Jan 04 2015 *) PROG (MAGMA) [n: n in [0..100]|IsPrime(n^2-2*n+5)] // Vincenzo Librandi, Nov 16 2010 (PARI) is(n)=isprime(n^2-2*n+5) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A005473 gives primes, A007591. Sequence in context: A054409 A344001 A152973 * A274170 A173144 A049015 Adjacent sequences:  A089744 A089745 A089746 * A089748 A089749 A089750 KEYWORD nonn,easy AUTHOR Giovanni Teofilatto, Jan 08 2004 STATUS approved

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Last modified June 30 03:34 EDT 2022. Contains 354913 sequences. (Running on oeis4.)