A140737 Triangle read by rows, X^n * [1,0,0,0,...]; where X = an infinite tridiagonal matrix with (1,1,1,...) in the main and subdiagonals and (1,0,1,0,1,...) in the subsubdiagonal.

1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 3, 6, 4, 5, 1, 1, 1, 4, 10, 10, 15, 6, 7, 1, 1, 1, 5, 15, 20, 35, 21, 28, 8, 9, 1, 1, 1, 6, 21, 35, 70, 56, 84, 36, 45, 10, 11, 1, 1, 1, 7, 28, 56, 126, 126, 210, 120, 165, 55, 66, 12, 13, 1, 1

Offset: 1

Author

Gary W. Adamson and Roger L. Bagula, May 25 2008

Keywords

• nonn
• tabf

Examples

			First few rows of the triangle are:
1;
1, 1, 1;
1, 2, 3, 1, 1;
1, 3, 6, 4, 5, 1, 1;
1, 4, 10, 10, 15, 6, 7, 1, 1;
1, 5, 15, 20, 35, 21, 28, 8, 9, 1, 1;
1, 6, 21, 35, 70, 56, 84, 36, 45, 10, 11, 1, 1;
1, 7, 28, 56, 126, 126, 210, 120, 165, 55, 66, 12, 13, 1, 1;
...
		

Crossrefs

Cf. A140736 (reversed rows), A001906 (row sums).