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 A089761 #14 Aug 14 2017 23:30:37 %S A089761 1,1,4,22,58,58,58,54972,68112,4748632,861066640,861066640,861066640, %T A089761 861066640,861066640 %N A089761 Smallest k such that k*i^2 + 1 is prime for i = 1 to n. %C A089761 a(16) > 1.4*10^13. [_Max Alekseyev_] %p A089761 for n from 1 to 10 do for k from 1 do f:=0: for i from 1 to n do if not isprime(k*i^2+1) then f:=1: break fi od: if f=0 then printf("%d, ",k): break fi od od: # C. Ronaldo %Y A089761 Cf. A124417. %K A089761 hard,more,nonn %O A089761 1,3 %A A089761 _Amarnath Murthy_, Nov 22 2003 %E A089761 Corrected and extended by C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 26 2004 %E A089761 a(11)-a(15) from _Donovan Johnson_, Sep 27 2008