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 A154686 #20 Sep 08 2022 08:45:40 %S A154686 1,2,4,5,7,12,13,20,23,25,27,28,32,33,34,35,39,42,44,47,48,49,50,54, %T A154686 57,75,79,82,88,89,92,95,98,99,100,103,109,110,114,117,119,120,123, %U A154686 132,134,137,139,147,148,160,169,172,180,189,190,193,194,200,202,203,204,205 %N A154686 Numbers k such that k^3 + 2*k^2 + k + 1 is prime. %C A154686 One less than the entry in A111501. - _R. J. Mathar_, Jan 05 2011 %H A154686 Vincenzo Librandi, <a href="/A154686/b154686.txt">Table of n, a(n) for n = 1..1000</a> %t A154686 Select[Range[0, 100], PrimeQ[#^3 + 2 #^2 + # + 1]&] (* _Vincenzo Librandi_, Sep 24 2012 *) %o A154686 (Magma) [n: n in [0..210] | IsPrime(n^3+2*n^2+n+1)]; // _Vincenzo Librandi_, Sep 24 2012 %o A154686 (PARI) is(n)=isprime(n^3+2*n^2+n+1) \\ _Charles R Greathouse IV_, May 22 2017 %Y A154686 Cf. A111501, A162292 (associated primes). %K A154686 nonn,easy %O A154686 1,2 %A A154686 _Vincenzo Librandi_, Jan 19 2009