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.
{a(n)=sum(k=0,(n+1)\2,binomial(2*n-2*k,n-k)/(n-k+1)*binomial(2*k,k)/(k+1) *(k+1)!*binomial(n+1,2*k)/2^k)} \\ Paul D. Hanna, Feb 18 2007
T(n,k)=[T(n-1,k),T(n-1,k+1),..,T(n-1,n-1)]*[T(k+1,k+1),T(k+2,k+1),..,T(n,k+1)]: 12 = [3,2,1]*[1,2,5] = 3*1 + 2*2 + 1*5; 21 = [5,3,1]*[1,3,7] = 5*1 + 3*3 + 1*7; 102 = [21,7,4,1]*[1,3,7,32] = 21*1 + 7*3 + 4*7 + 1*32; 158 = [32,9,5,1]*[1,4,9,45] = 32*1 + 9*4 + 5*9 + 1*45. Triangle begins: 1; 1, 1; 3, 2, 1; 12, 5, 3, 1; 58, 21, 7, 4, 1; 321, 102, 32, 9, 5, 1; 1963, 579, 158, 45, 11, 6, 1; 13053, 3601, 933, 226, 60, 13, 7, 1; 92946, 24426, 5939, 1395, 306, 77, 15, 8, 1; 702864, 176858, 41385, 9097, 1977, 398, 96, 17, 9, 1; 5599204, 1359906, 306070, 65310, 13195, 2691, 502, 117, 19, 10, 1; 46746501, 10996740, 2403792, 494022, 97701, 18353, 3549, 618, 140, 21, 11, 1; 407019340, 93136545, 19799468, 3970878, 755834, 140178, 24691, 4563, 746, 165, 23, 12, 1; ...
{T(n,k)=if(n==k,1,if(n==k+1,n, sum(j=0,n-k-1,T(n-1,j+k)*T(j+k+1,k+1))))}
for(n=0,12,for(k=0,n, print1(T(n,k),", "));print(""))
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