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 A176862 #4 Jul 22 2025 07:59:49
%S A176862 2,5,5,37,-16,37,239,-50,-50,239,1801,-492,180,-492,1801,15119,-4186,
%T A176862 714,714,-4186,15119,141121,-40336,8568,-2688,8568,-40336,141121,
%U A176862 1451519,-423342,90504,-13104,-13104,90504,-423342,1451519
%N A176862 A symmetrical triangle sequence:t(n,m)=(-1)^m*(n - m)!*Binomial[n - 1, m] + (-1)^(n - m + 1)*(n - (n - m + 1))!*Binomial[n - 1, n - m + 1].
%C A176862 Row sums are:
%C A176862 {2, 10, 58, 378, 2798, 23294, 216018, 2211154,...}.
%D A176862 F. S. Roberts, Applied Combinatorics, Prentice-Hall, 1984, p. 576 and 270.
%F A176862 t(n,m)=(-1)^m*(n - m)!*Binomial[n - 1, m] + (-1)^(n - m + 1)*(n - (n - m + 1))!*Binomial[n - 1, n - m + 1]
%e A176862 {2},
%e A176862 {5, 5},
%e A176862 {37, -16, 37},
%e A176862 {239, -50, -50, 239},
%e A176862 {1801, -492, 180, -492, 1801},
%e A176862 {15119, -4186, 714, 714, -4186, 15119},
%e A176862 {141121, -40336, 8568, -2688, 8568, -40336, 141121},
%e A176862 {1451519, -423342, 90504, -13104, -13104, 90504, -423342, 1451519}
%t A176862 t[n_, m_] := (-1)^m*(n - m)!*Binomial[n - 1, m] + (-1)^(n - m + 1)*(n - (n - m + 1))!*Binomial[n - 1, n - m + 1];
%t A176862 Table[Table[t[n, m], {m, 2, n - 1}], {n, 3, 10}];
%t A176862 Flatten[%]
%Y A176862 Cf. A132159
%K A176862 sign,tabl,uned
%O A176862 3,1
%A A176862 _Roger L. Bagula_, Apr 27 2010