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 A126571 #14 Oct 30 2019 17:41:04
%S A126571 1,2,3,3,5,4,4,7,5,7,5,9,7,9,6,6,11,8,11,7,17,7,13,10,13,8,19,8,8,15,
%T A126571 11,15,9,23,9,15,9,17,13,17,11,25,10,17,13,10,19,14,19,12,29,11,19,14,
%U A126571 23,11,21,16,21,13,31,12,21,16,27,12,12,23,17,23,14,35,13,23,17,29,13,35
%N A126571 Triangle where the m-th term in row n is the n-th integer from among those positive integers coprime to m.
%H A126571 Michael De Vlieger, <a href="/A126571/b126571.txt">Table of n, a(n) for n = 1..11325</a> (rows 1 <= n <= 150).
%e A126571 The fifth positive integer coprime to 1 is 5. The fifth positive integer coprime to 2 is 9. The fifth positive integer coprime to 3 is 7. The fifth positive integer coprime to 4 is 9. And the fifth positive integer coprime to 5 is 6. So row 5 of the triangle is (5,9,7,9,6).
%e A126571 From _Michael De Vlieger_, Aug 21 2017: (Start)
%e A126571 Triangle begins:
%e A126571 1
%e A126571 2 3
%e A126571 3 5 4
%e A126571 4 7 5 7
%e A126571 5 9 7 9 6
%e A126571 6 11 8 11 7 17
%e A126571 7 13 10 13 8 19 8
%e A126571 8 15 11 15 9 23 9 15
%e A126571 9 17 13 17 11 25 10 17 13
%e A126571 10 19 14 19 12 29 11 19 14 23
%e A126571 11 21 16 21 13 31 12 21 16 27 12
%e A126571 12 23 17 23 14 35 13 23 17 29 13 35
%e A126571 (End)
%t A126571 f[m_, n_] := Block[{k = 0, c = n},While[c > 0,k++;While[GCD[k, m] > 1, k++ ];c--;];k];Flatten@Table[f[m, n], {n, 12}, {m, n}] (* _Ray Chandler_, Dec 29 2006 *)
%Y A126571 Cf. A126572, A077581.
%K A126571 nonn,tabl
%O A126571 1,2
%A A126571 _Leroy Quet_, Dec 28 2006
%E A126571 Extended by _Ray Chandler_, Dec 29 2006