

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.


2



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
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,6


COMMENTS

Row sums = F(2n), A001906: (1, 3, 8, 21, 55, 144,...).


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, A001906.
Sequence in context: A202603 A279612 A261019 * A108756 A106178 A305807
Adjacent sequences: A140734 A140735 A140736 * A140738 A140739 A140740


KEYWORD

nonn,tabl


AUTHOR

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


STATUS

approved



