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 A199366 #18 Sep 01 2025 14:15:22 %S A199366 1,2,3,5,6,11,12,15,18,30,32,45,48,51,63,66,87,90,98,101,113,116,122, %T A199366 125,132,150,153,155,156,161,170,171,173,183,195,198,203,213,233,237, %U A199366 243,246,260,266,282,288,291,297,300,302,305,308,321,335,341,342,347,366,371,377,381,386,393,398,401,402,407,408,411,423,425,426,437,443,452,455,456 %N A199366 Numbers k such that 4*k^3-1 is prime. %C A199366 See comment in A199307. %H A199366 Vincenzo Librandi, <a href="/A199366/b199366.txt">Table of n, a(n) for n = 1..1000</a> %t A199366 Select[Range[0, 1000], PrimeQ[4#^3 - 1]&] (* _Vincenzo Librandi_, Jan 07 2013 *) %o A199366 (Magma) [n: n in [0..500] | IsPrime(4*n^3-1)]; // _Vincenzo Librandi_, Jan 07 2013 %o A199366 (PARI) is(n)=isprime(4*n^3-1) \\ _Charles R Greathouse IV_, May 22 2017 %Y A199366 Cf. A199307, A199367. %K A199366 nonn,easy,changed %O A199366 1,2 %A A199366 _N. J. A. Sloane_, Nov 05 2011