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 A386825 #11 Aug 13 2025 22:16:54
%S A386825 1,6,1,54,12,1,540,135,18,1,5670,1512,252,24,1,61236,17010,3240,405,
%T A386825 30,1,673596,192456,40095,5940,594,36,1,7505784,2189187,486486,81081,
%U A386825 9828,819,42,1,84440070,25019280,5837832,1061424,147420,15120,1080,48,1,956987460,287096238
%N A386825 Triangle read by rows: T(n,k) = 3^(n-k)*C(2*n,n-k).
%C A386825 Row sums are A386826.
%F A386825 T(n,k) = 3^(n-k)*A094527(n,k).
%e A386825 Triangle begins:
%e A386825 1;
%e A386825 6, 1;
%e A386825 54, 12, 1;
%e A386825 540, 135, 18, 1;
%e A386825 5670, 1512, 252, 24, 1;
%e A386825 61236, 17010, 3240, 405, 30, 1;
%e A386825 673596, 192456, 40095, 5940, 594, 36, 1;
%e A386825 7505784, 2189187, 486486, 81081, 9828, 819, 42, 1;
%e A386825 ...
%t A386825 Flatten[Table[3^(n-k) Binomial[2n, n-k], {n, 0, 9}, {k, 0, n}]]
%Y A386825 Cf. A094527, A128417, A386826.
%K A386825 nonn,tabl
%O A386825 0,2
%A A386825 _Enrique Navarrete_, Aug 04 2025