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 A087554 #8 Oct 19 2017 03:14:22 %S A087554 1,2,4,4,6,6,10,9,12,10,18,13,24,14,16,16,18,21,22,20,22,28,26,24,28, %T A087554 26,28,34,32,33,36,36,34,37,42,36,40,39,48,40,42,46,46,47,48,51,50,54, %U A087554 52,51,56,55,56,54,58,56,58,61,60,67,66,63,66,67,68,66,70,75,70,79,72,79 %N A087554 a(n) = smallest number k >= n such that nk + 1 is a prime. %C A087554 Conjectures: (1) k < 2n. (2) For every r, there exists a number S, nr < S < n(r+1) such that nS + 1 is prime. %p A087554 for n from 1 to 120 do k := n: while(not isprime(n*k+1)) do k := k+1:od:a[n] := k:od:seq(a[l],l=1..120); # _Sascha Kurz_ %Y A087554 Cf. A034693. %K A087554 nonn %O A087554 1,2 %A A087554 _Amarnath Murthy_, Sep 13 2003 %E A087554 Edited by _Ray Chandler_ and _Don Reble_, Sep 16 2003