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 A115928 #11 Mar 12 2022 13:06:43
%S A115928 1,2,3,4,5,7,9,8,11,13,15,14,17,19,23,6,25,29,31,12,35,37,41,16,21,43,
%T A115928 47,10,27,49,53,20,33,59,61,26,45,67,71,22,39,73,79,28,51,55,83,32,57,
%U A115928 65,77,34,69,89,91,38,75,97,101,44,63,85,103,46,81,195,107,52,87,109,113,40,93,119
%N A115928 Smallest number which is coprime to the last four predecessors and not occurring earlier; a(1)=1, a(2)=2, a(3)=3 & a(4)=4.
%t A115928 f[s_] := Block[{k = 1, l = Take[s,-4]}, While[ Union[ GCD[k, l]] != {1} || MemberQ[s,k], k++]; Append[s,k]]; Nest[f, {1,2,3,4}, 70]
%Y A115928 Cf. A084937, A103683.
%K A115928 easy,nonn
%O A115928 1,2
%A A115928 _Robert G. Wilson v_, Jun 26 2011