A131948 Triangle T(n,k) = 2*A002024(n+1,k+1) + A007318(n,k) - 2, read by rows.

1, 3, 3, 5, 6, 5, 7, 9, 9, 7, 9, 12, 14, 12, 9, 11, 15, 20, 20, 15, 11, 13, 18, 27, 32, 27, 18, 13, 15, 21, 35, 49, 49, 35, 21, 15, 17, 24, 44, 72, 86, 72, 44, 24, 17, 19, 27, 54, 102, 144, 144, 102, 54, 27, 19

Offset

0,2

Comments

Row sums = A131949.

Links

Table of n, a(n) for n=0..54.

Formula

2*A002024 + A007318 - 2*A000012 as infinite lower triangular matrices.

Example

First few rows of the triangle are:
1;
3, 3;
5, 6, 5;
7, 9, 9, 7;
9, 12, 14, 12, 9;
11, 15, 20, 20, 15, 11;
13, 18, 27, 32, 27, 18, 13;
15, 21, 35, 49, 49, 35, 21, 15;
...

Crossrefs

Cf. A002024, A007318, A131949.

Sequence in context: A128444 A317745 A204250 * A134636 A088564 A161560

Adjacent sequences: A131945 A131946 A131947 * A131949 A131950 A131951

Keyword

nonn,tabl

Author

Gary W. Adamson, Jul 30 2007

Status

approved