A134634 Triangle formed by Pascal's rule with borders = A000108.
1, 1, 1, 2, 2, 2, 5, 4, 4, 5, 14, 9, 8, 9, 14, 42, 23, 17, 17, 23, 42, 132, 65, 40, 34, 40, 65, 132, 429, 197, 105, 74, 74, 105, 197, 429, 1430, 626, 302, 179, 148, 179, 302, 626, 1430, 4862, 2056, 928, 481, 327, 327, 481, 928, 2056, 4862, 16796, 6918, 2984, 1409, 808, 654, 808, 1409, 2984, 6918, 16796, 58786, 23714, 9902, 4393, 2217, 1462, 1462, 2217, 4393, 9902, 23714, 58786
Offset: 0
Examples
First few rows of the triangle: 1; 1, 1; 2, 2, 2; 5, 4, 4, 5; 14, 9, 8, 9, 14; 42, 23, 17, 17, 23, 42; 132, 65, 40, 34, 40, 65, 132; ...
Formula
Triangle, given right and left borders consist of the Catalan sequence, A000108; then T(n,k) = T(n-1,k) + T(n-1,k-1).
Extensions
Recomputed by N. J. A. Sloane, Feb 18 2013
Comments