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 A196230 #13 May 29 2022 15:49:30
%S A196230 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,83,89,97,
%T A196230 101,107,113,127,131,149,151,173,197,199,223,227,251,257,281,313,347,
%U A196230 383,421,461,503,547,593,641,691,743,797,853,911,971,1033,1097,1163,1231,1301,1373,1447,1523,1601
%N A196230 Euler primes: values of x^2 - x + k for x = 1..k-1, where k is one of Euler's "lucky" numbers 2, 3, 5, 11, 17, 41.
%C A196230 See A198245 for another sequence of "Euler primes". - _N. J. A. Sloane_, May 29 2022
%C A196230 All terms are prime numbers.
%C A196230 k is an Euler "lucky" number iff 4k-1 is a Heegner number 1, 2, 3, 7, 11, 19, 43, 67, 163.
%C A196230 See A014556 (Euler's "lucky" numbers) and A003173 (Heegner numbers) for additional references and links.
%D A196230 J. H. Conway and R. K. Guy, The Book of Numbers, Copernicus Press, NY, 1996, p. 225.
%e A196230 The prime 1601 is a member because 40^2-40+41 = 1601.
%t A196230 H = {2, 3, 5, 11, 17, 41}; Union[Flatten[Table[ Array[ #^2 - # + H[[k]] &, H[[k]] - 1], {k, 1, 6}]]]
%Y A196230 Cf. A003173, A014556, A198245.
%K A196230 nonn,fini,full
%O A196230 1,1
%A A196230 _Jonathan Sondow_, Oct 29 2011