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 A154686 Numbers k such that k^3 + 2*k^2 + k + 1 is prime. 3
 1, 2, 4, 5, 7, 12, 13, 20, 23, 25, 27, 28, 32, 33, 34, 35, 39, 42, 44, 47, 48, 49, 50, 54, 57, 75, 79, 82, 88, 89, 92, 95, 98, 99, 100, 103, 109, 110, 114, 117, 119, 120, 123, 132, 134, 137, 139, 147, 148, 160, 169, 172, 180, 189, 190, 193, 194, 200, 202, 203, 204, 205 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS One less than the entry in A111501. - R. J. Mathar, Jan 05 2011 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 MATHEMATICA Select[Range[0, 100], PrimeQ[#^3 + 2 #^2 + # + 1]&] (* Vincenzo Librandi, Sep 24 2012 *) PROG (Magma) [n: n in [0..210] | IsPrime(n^3+2*n^2+n+1)]; // Vincenzo Librandi, Sep 24 2012 (PARI) is(n)=isprime(n^3+2*n^2+n+1) \\ Charles R Greathouse IV, May 22 2017 CROSSREFS Cf. A111501, A162292 (associated primes). Sequence in context: A257033 A039674 A090649 * A165196 A007062 A121817 Adjacent sequences: A154683 A154684 A154685 * A154687 A154688 A154689 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Jan 19 2009 STATUS approved

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Last modified November 27 06:50 EST 2022. Contains 358362 sequences. (Running on oeis4.)