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

0,3

Comments

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

Links

Table of n, a(n) for n=0..41.

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.

Example

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

Sequence in context: A299161 A327249 A173108 * A363739 A257459 A372494

Adjacent sequences: A173108 A173109 A173110 * A173112 A173113 A173114

Keyword

nonn,tabl

Author

Gary W. Adamson, Feb 09 2010

Status

approved