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 A156789 #8 Sep 08 2022 08:45:41
%S A156789 1,1,4,6,1,8,36,80,70,1,12,90,400,1050,1512,924,1,16,168,1120,4900,
%T A156789 14112,25872,27456,12870,1,20,270,2400,14700,63504,194040,411840,
%U A156789 579150,486200,184756,1,24,396,4400,34650,199584,853776,2718144,6370650,10696400,12193896,8465184,2704156
%N A156789 Irregular triangle, read by rows, T(n, k) = binomial(2*n, k)*binomial(2*k, k).
%C A156789 Row sums are A137341: {1, 11, 195, 3989, 86515, 1936881, 44241261, 1024642875, 23973456915, 565280386625, 13411044301945, ...}.
%D A156789 J. Riordan, Combinatorial Identities, Wiley, 1968, p.77.
%H A156789 G. C. Greubel, <a href="/A156789/b156789.txt">Rows n = 0..100 of triangle, flattened</a>
%F A156789 T(n, k) = binomial(2*n, k)*binomial(2*k, k).
%e A156789 Triangle begins as:
%e A156789 1;
%e A156789 1, 4, 6;
%e A156789 1, 8, 36, 80, 70;
%e A156789 1, 12, 90, 400, 1050, 1512, 924;
%e A156789 1, 16, 168, 1120, 4900, 14112, 25872, 27456, 12870;
%e A156789 1, 20, 270, 2400, 14700, 63504, 194040, 411840, 579150, 486200, 184756;
%p A156789 seq(seq( binomial(2*n, k)*binomial(2*k, k), k=0..2*n), n=0..10); # _G. C. Greubel_, Nov 30 2019
%t A156789 Table[Binomial[2*n, k]*Binomial[2*k, k], {n,0,10}, {k,0,2*n}]//Flatten
%o A156789 (PARI) T(n,k) = binomial(2*n, k)*binomial(2*k, k); \\ _G. C. Greubel_, Nov 30 2019
%o A156789 (Magma) [Binomial(2*n, k)*Binomial(2*k, k): k in [0..2*n], n in [0..10]]; // _G. C. Greubel_, Nov 30 2019
%o A156789 (Sage) [[binomial(2*n, k)*binomial(2*k, k) for k in (0..2*n)] for n in (0..10)] # _G. C. Greubel_, Nov 30 2019
%o A156789 (GAP) Flat(List([0..10], n-> List([0..2*n], k->Binomial(2*n, k)*Binomial(2*k, k) ))); # _G. C. Greubel_, Nov 30 2019
%K A156789 nonn,tabf
%O A156789 0,3
%A A156789 _Roger L. Bagula_, Feb 15 2009