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 A163674 #14 Sep 08 2022 08:45:47
%S A163674 13,16,21,19,26,33,22,31,40,49,25,36,47,58,69,28,41,54,67,80,93,31,46,
%T A163674 61,76,91,106,121,34,51,68,85,102,119,136,153,37,56,75,94,113,132,151,
%U A163674 170,189,40,61,82,103,124,145,166,187,208,229,43,66,89,112,135,158,181
%N A163674 Triangle T(n,m) = 2*m*n + m + n + 9 read by rows.
%C A163674 2*T(m,n) - 17 =(2*n+1)*(2*m+1) and 2*T(n,n) - 17 is a square. Also:
%C A163674 first column: A112414;
%C A163674 second column: A016861;
%C A163674 third column: A017041;
%C A163674 fourth column: A017209. [_Vincenzo Librandi_, Nov 20 2012]
%H A163674 Vincenzo Librandi, <a href="/A163674/b163674.txt">Rows n = 1..100, flattened</a>
%F A163674 T(n,m) = A163657(n,m) + 1.
%e A163674 Triangle begins:
%e A163674 13;
%e A163674 16, 21;
%e A163674 19, 26, 33;
%e A163674 22, 31, 40, 49;
%e A163674 25, 36, 47, 58, 69;
%e A163674 28, 41, 54, 67, 80, 93;
%e A163674 31, 46, 61, 76, 91, 106, 121;
%e A163674 34, 51, 68, 85, 102, 119, 136, 153;
%t A163674 t[n_,k_]:=2 n*k + n + k + 9; Table[t[n, k], {n, 15}, {k, n}]//Flatten (* _Vincenzo Librandi_, Nov 20 2012 *)
%o A163674 (Magma) [2*n*k + n + k + 9: k in [1..n], n in [1..11]]; // _Vincenzo Librandi_, Nov 20 2012
%o A163674 (PARI) for(n=1,10, for(m=1,n, print1(2*m*n + m + n + 9, ", "))) \\ _G. C. Greubel_, Aug 02 2017
%Y A163674 Cf. A016861, A017041, A017209, A112414, A153051, A163657.
%K A163674 nonn,easy,tabl
%O A163674 1,1
%A A163674 _Vincenzo Librandi_, Aug 03 2009
%E A163674 Edited by _R. J. Mathar_, Oct 12 2009