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 A173591 #9 Jan 25 2019 04:10:44 %S A173591 2,1,1,0,-6,0,1,-3,-3,1,2,-18,110,-18,2,1,-35,-159,-159,-35,1,0,10, %T A173591 3000,-5790,3000,10,0,1,-139,-15091,27457,27457,-15091,-139,1,2,30, %U A173591 110454,-595250,578402,-595250,110454,30,2,1,5,-715167,7576241,-5255603,7576241,-715167,5,1 %N A173591 T(n, k) = k^n*U(n, (1/k - k)/2) + (n + 1)^(k - 1)*U(k - 1, (1/(n + 1) - n - 1)/2), where U(n,x) is the n-th Chebyshev polynomial of the second kind, square array read by antidiagonals (n >= 0, k >= 1). %F A173591 Let b(n,k) = (k^n)*U(n, (1/k - k)/2). Then T(n,k) = b(n,k) + b(k-1,n+1). %e A173591 Square array begins: %e A173591 n\k | 1 2 3 4 5 6 ... %e A173591 ---------------------------------------------------- %e A173591 0 | 2 1 0 1 2 1 ... %e A173591 1 | 1 -6 -3 -18 -35 10 ... %e A173591 2 | 0 -3 110 -159 3000 -15091 ... %e A173591 3 | 1 -18 -159 -5790 27457 -595250 ... %e A173591 4 | 2 -35 3000 27457 578402 -5255603 ... %e A173591 5 | 1 10 -15091 -595250 -5255603 -92967910 ... %e A173591 6 | 0 -139 110454 7576241 156747480 1344158389 ... %e A173591 ... %t A173591 p[x_, q_] = 1/(x^2 - (1/q - q)*x + 1); %t A173591 a = Table[Table[n^m*SeriesCoefficient[Series[p[x, n], {x, 0, 50}], m], {m, 0, 20}], {n, 1, 21}]; %t A173591 b = (a + Transpose[a]); %t A173591 Flatten[Table[Table[b[[m, n - m + 1]], {m, 1, n}], {n, 1, 10}]] %o A173591 (Maxima) %o A173591 T(n, k) := k^n*chebyshev_u(n, (1/k - k)/2) + (n + 1)^(k - 1)*chebyshev_u(k - 1, (1/(n + 1) - n - 1)/2)$ %o A173591 create_list(T(n - k + 1, k), n, 0, 12, k, 1, n + 1); %o A173591 /* _Franck Maminirina Ramaharo_, Jan 24 2019 */ %Y A173591 Cf. A173588, A173590. %K A173591 sign,easy,tabl %O A173591 0,1 %A A173591 _Roger L. Bagula_, Feb 22 2010 %E A173591 Edited by _Franck Maminirina Ramaharo_, Jan 24 2019