A173111 Triangle read by rows, A173108 * the diagonalized variant of A173110.

1, 1, 2, 1, 5, 1, 15, 2, 3, 52, 5, 3, 203, 15, 6, 6, 877, 52, 15, 6, 4140, 203, 45, 12, 20, 21147, 877, 156, 30, 20, 115975, 4140, 609, 90, 40, 60, 678570, 21147, 2631, 312, 100, 60

Offset: 0

Author

Gary W. Adamson, Feb 09 2010

Keywords

• nonn
• tabl

Comments

Row sums = A173110: (1, 1, 3, 6, 20, 60, 230, 950, 4420, 22230,...).

Examples

			First few rows of the triangle =
1;
1;
2, 1;
5, 1;
15, 2, 3;
52, 5, 3;
203, 15, 6, 6;
877, 52, 15, 6;
4140, 203, 45, 12, 20;
21147, 877, 156, 30, 20;
115975, 4140, 609, 90, 40, 60;
678570, 21147, 2631, 312, 100, 60;
...
Example: row 7 = termwise products of (877, 52, 5, 1) and (1, 1, 3, 6) =
(877, 52, 15, 6); where (877, 52, 5, 1) = row 7 of triangle A173108, and
(1, 1, 3, 6) = the first four terms of sequence A173109.
		

Crossrefs

A173108, A173109, A173110

Formula

Let triangle A173108 = Q, and M = an infinite lower triangular matrix with A173110 as the rightmost diagonal and the rest zeros. Triangle A173111 = Q*M.