cp's OEIS Frontend

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.

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).

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%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