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 A156918 #7 Jan 08 2022 03:42:12
%S A156918 1,1,-1,1,1,-6,7,-2,1,1,-23,46,-47,26,-3,1,1,-76,306,-536,459,-232,82,
%T A156918 -4,1,1,-237,1919,-5046,6965,-5995,3109,-958,247,-5,1,1,-722,11265,
%U A156918 -44634,91730,-113538,90417,-49398,17778,-3630,737,-6,1,1,-2179,62836,-381037,1099549,-1878718,2123525,-1658537,898985,-346886,93377,-13109,2200,-7,1
%N A156918 Triangle formed by coefficients of the expansion of p(x,n) = (1+x-x^2)^(n+1)*Sum_{j >= 0} (2*j+1)^n*(-x + x^2)^j.
%C A156918 Row sums are one.
%H A156918 G. C. Greubel, <a href="/A156918/b156918.txt">Rows n = 0..50 of the irregular triangle, flattened</a>
%F A156918 T(n, k) = coefficients of the expansion of p(x, n), where p(x,n) = (1+x-x^2)^(n + 1)*Sum_{j >= 0} (2*j+1)^n*(-x + x^2)^j.
%F A156918 T(n, 1) = (-1)*A060188(n), for n >= 2. - _G. C. Greubel_, Jan 07 2022
%e A156918 Irregular triangle begins as:
%e A156918 1;
%e A156918 1, -1, 1;
%e A156918 1, -6, 7, -2, 1;
%e A156918 1, -23, 46, -47, 26, -3, 1;
%e A156918 1, -76, 306, -536, 459, -232, 82, -4, 1;
%e A156918 1, -237, 1919, -5046, 6965, -5995, 3109, -958, 247, -5, 1;
%e A156918 1, -722, 11265, -44634, 91730, -113538, 90417, -49398, 17778, -3630, 737, -6, 1;
%t A156918 p[x_, n_] = (1+x-x^2)^(n+1)*Sum[(2*k+1)^n*(-x+x^2)^k, {k, 0, Infinity}];
%t A156918 Table[CoefficientList[p[x, n], x], {n,0,10}]//Flatten
%o A156918 (Sage)
%o A156918 def T(n, k): return ( (1+x-x^2)^(n+1)*sum((2*j+1)^n*(x^2-x)^j for j in (0..2*n+1)) ).series(x, 2*n+2).list()[k]
%o A156918 flatten([1]+[[T(n, k) for k in (0..2*n)] for n in (1..12)]) # _G. C. Greubel_, Jan 07 2022
%Y A156918 Cf. A060188, A156896, A156890, A156901.
%K A156918 sign,tabf
%O A156918 0,6
%A A156918 _Roger L. Bagula_, Feb 18 2009
%E A156918 Edited by _G. C. Greubel_, Jan 07 2022