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 A143827 #8 Aug 23 2025 21:51:22
%S A143827 1,2,3,4,5,9,11,12,14,17,18,19,21,23,25,26,28,31,32,38,40,46,49,51,54,
%T A143827 56,59,63,66,67,70,77,79,80,82,86,89,93,94,96,98,100,102,103,107,110,
%U A143827 114,116,119,121,124,128,133,135,137,140,144,147,150,152,156,161,166
%N A143827 Numbers k such that 8*k^2 - 1 is prime.
%C A143827 Contains the even terms of A066049 divided by 2. - _R. J. Mathar_, Sep 04 2008
%t A143827 p = 8; a = {}; Do[k = p x^2 - 1; If[PrimeQ[k], AppendTo[a, x]], {x, 1, 1000}]; a
%o A143827 (PARI) is(n)=isprime(8*n^2-1) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y A143827 Cf. A090686, A090684.
%K A143827 nonn,changed
%O A143827 1,2
%A A143827 _Artur Jasinski_, Sep 02 2008