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.

A378062 Array read by ascending antidiagonals: A(n, k) = (n + 1)*binomial(2*k + n - 1, k - 1)^2 / (2*k + n - 1) for k > 0, and A(n, 0) = 0.

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%I A378062 #9 Dec 08 2024 17:22:13
%S A378062 0,0,1,0,1,3,0,1,8,20,0,1,15,75,175,0,1,24,189,784,1764,0,1,35,392,
%T A378062 2352,8820,19404,0,1,48,720,5760,29700,104544,226512,0,1,63,1215,
%U A378062 12375,81675,382239,1288287,2760615,0,1,80,1925,24200,196625,1145144,5010005,16359200,34763300
%N A378062 Array read by ascending antidiagonals: A(n, k) = (n + 1)*binomial(2*k + n - 1, k - 1)^2 / (2*k + n - 1) for k > 0, and A(n, 0) = 0.
%e A378062 Array A(n, k) starts:
%e A378062   [0] 0, 1,  3,   20,   175,    1764,    19404, ... A000891
%e A378062   [1] 0, 1,  8,   75,   784,    8820,   104544, ... A145600
%e A378062   [2] 0, 1, 15,  189,  2352,   29700,   382239, ... A145601
%e A378062   [3] 0, 1, 24,  392,  5760,   81675,  1145144, ... A145602
%e A378062   [4] 0, 1, 35,  720, 12375,  196625,  3006003, ... A145603
%e A378062   [5] 0, 1, 48, 1215, 24200,  429429,  7154784, ...
%e A378062   [6] 0, 1, 63, 1925, 44044,  869505, 15767024, ...
%e A378062   [7] 0, 1, 80, 2904, 75712, 1656200, 32626944, ...
%e A378062 .
%e A378062 Seen as a triangle, T(n, k) = A(n-k, k). Compare the descending antidiagonals of A378061.
%e A378062   [0] 0;
%e A378062   [1] 0, 1;
%e A378062   [2] 0, 1,  3;
%e A378062   [3] 0, 1,  8,  20;
%e A378062   [4] 0, 1, 15,  75,  175;
%e A378062   [5] 0, 1, 24, 189,  784,  1764;
%e A378062   [6] 0, 1, 35, 392, 2352,  8820,  19404;
%e A378062   [7] 0, 1, 48, 720, 5760, 29700, 104544, 226512;
%p A378062 A := (n, k) -> ifelse(k = 0, 0, (n + 1)*binomial(2*k + n - 1, k - 1)^2/(2*k + n - 1)):
%p A378062 for n from 0 to 7 do seq(A(n, k), k = 0..7);
%t A378062 A[n_, k_] := If[k==0, 0, (n + 1)*Binomial[2*k + n - 1, k - 1]^2 / (2*k + n - 1)]; Table[A[n-k,k],{n,0,9},{k,0,n}]//Flatten (* _Stefano Spezia_, Dec 08 2024 *)
%Y A378062 Rows: A000891, A145600, A145601, A145602, A145603.
%Y A378062 Columns: A005563, A005565, A378061.
%K A378062 nonn,tabl
%O A378062 0,6
%A A378062 _Peter Luschny_, Dec 07 2024