A162303 Product matrix [C(k,n-k)]*A001263.

1, 1, 1, 2, 4, 1, 3, 12, 8, 1, 5, 31, 39, 13, 1, 8, 73, 148, 93, 19, 1, 13, 162, 481, 486, 186, 26, 1, 21, 344, 1406, 2080, 1274, 332, 34, 1, 34, 707, 3803, 7741, 6920, 2873, 547, 43, 1

Offset

0,4

Comments

First column is A000045. Row sums are A052705(n+2).

Links

Table of n, a(n) for n=0..44.

Formula

Number triangle T(n,k)=sum{j=0..n, C(j,n-j)*C(j+1,k)*C(j+1,k+1)/(j+1)}.

Example

Triangle begins
1,
1, 1,
2, 4, 1,
3, 12, 8, 1,
5, 31, 39, 13, 1,
8, 73, 148, 93, 19, 1,
13, 162, 481, 486, 186, 26, 1,
21, 344, 1406, 2080, 1274, 332, 34, 1

Crossrefs

Sequence in context: A308244 A117297 A112973 * A128570 A371767 A157284

Adjacent sequences: A162300 A162301 A162302 * A162304 A162305 A162306

Keyword

easy,nonn,tabl

Author

Paul Barry, Jun 30 2009

Status

approved