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 A263730 #23 Dec 27 2016 19:09:35
%S A263730 0,0,1,0,2,0,1,3,0,4,0,1,2,5,0,6,0,1,3,7,0,2,8,0,1,4,9,0,10,0,1,2,3,5,
%T A263730 11,0,12,0,1,6,13,0,2,4,14,0,1,3,7,15,0,16,0,1,2,5,8,17,0,18,0,1,3,4,
%U A263730 9,19,0,2,6,20,0,1,10,21,0,22,0,1,2,3,5,7,11,23,0,4,24,0,1,12,25
%N A263730 Irregular triangle read by rows in which row n > 1 lists k such that (k^2 + k*n)/(k + 1) is an integer.
%C A263730 Minimal value of k is 0 and maximal value of k is n - 2 for n-th row.
%C A263730 Length of rows gives A000005.
%C A263730 Sum of rows gives A065608.
%H A263730 Harvey P. Dale, <a href="/A263730/b263730.txt">Table of n, a(n) for n = 2..1000</a>
%F A263730 a(n) = A027750(n) - 1.
%e A263730 n\k| 0 1 2 3 4 5 6 7 8 9 10
%e A263730 ---+------------------------------------------
%e A263730 0 | 0
%e A263730 1 | 0 1 2 3 4 5 6 7 8 9 10
%e A263730 2 | 0
%e A263730 3 | 0 1
%e A263730 4 | 0 2
%e A263730 5 | 0 1 3
%e A263730 6 | 0 4
%e A263730 7 | 0 1 2 5
%e A263730 8 | 0 6
%e A263730 9 | 0 1 3 7
%e A263730 10 | 0 2 8
%e A263730 11 | 0 1 4 9
%e A263730 12 | 0 10
%e A263730 13 | 0 1 2 3 5 11
%t A263730 Table[Select[Range[0,n-2],Divisible[#^2+n #,#+1]&],{n,30}]//Flatten (* _Harvey P. Dale_, Dec 27 2016 *)
%o A263730 (PARI) tabf(nn) = {for (n=2, nn, for (k=0, n, if (!((k^2 + k*n) % (k+1)), print1(k, ", "));); print(););} \\ _Michel Marcus_, Oct 25 2015
%Y A263730 Cf. A000005, A065608, A027750, A263729.
%K A263730 nonn,tabf
%O A263730 2,5
%A A263730 _Juri-Stepan Gerasimov_, Oct 25 2015