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 A126356 #10 Oct 10 2019 13:49:29
%S A126356 1,2,5,4,13,6,13,11,21,10,31,12,29,26,29,16,49,18,47,34,45,22,67,29,
%T A126356 53,38,61,28,107,30,61,52,69,48,103,36,77,61,97,40,143,42,93,82,93,46,
%U A126356 139,55,121,79,109,52,157,73,127,88,117,58,221,60,125,107,125,86,215,66,141
%N A126356 a(n) is the n-th integer from among the positive integers which are coprime to (n+1).
%e A126356 The positive integers which are coprime to 6 are 1,5,7,11,13,17,19,23,... The 5th of these is 13, which is a(5).
%t A126356 f[n_] := Block[{k = 0, c = n},While[c > 0,k++;While[GCD[k, n + 1] > 1, k++ ];c--;];k];Table[f[n], {n, 67}] (* _Ray Chandler_, Dec 29 2006 *)
%Y A126356 Cf. A069213, A126357.
%K A126356 nonn
%O A126356 1,2
%A A126356 _Leroy Quet_, Dec 26 2006
%E A126356 Extended by _Ray Chandler_, Dec 29 2006