Triangle of Narayana numbers T(n,k) = C(n-1,k-1)C(n,k-1)/k with 1<=k<=n, read by rows. Also called the Catalan triangle.
1, 1, 1, 1, 3, 1, 1, 6, 6, 1, 1, 10, 20, 10, 1, 1, 15, 50, 50, 15, 1, 1, 21, 105, 175, 105, 21
2 seqfan posts
Tue May 15 20:32:46 CEST 2012 [seqfan] Polynomials from a Carlitz-Riordan paper