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

1,6

Links

Table of n, a(n) for n=1..64.

Example

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).

Sequence in context: A202603 A279612 A261019 * A354009 A108756 A106178

Adjacent sequences: A140734 A140735 A140736 * A140738 A140739 A140740

Keyword

nonn,tabf

Author

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

Status

approved