A107030 Number triangle associated with the Riordan arrays (1/(1+x),x/(1+x)^k),k>=0.

1, 2, 1, 2, 2, 1, 2, 4, 2, 1, 2, 8, 6, 2, 1, 2, 16, 20, 8, 2, 1, 2, 32, 70, 38, 10, 2, 1, 2, 64, 252, 196, 62, 12, 2, 1, 2, 128, 924, 1062, 426, 92, 14, 2, 1, 2, 256, 3432, 5948, 3112, 792, 128, 16, 2, 1, 2, 512, 12870, 34120, 23686, 7302, 1326, 170, 18, 2, 1

Offset: 0

Author

Paul Barry, May 09 2005

Keywords

• easy
• nonn
• tabl

Examples

			Triangle begins
  1;
  2,  1;
  2,  2,  1;
  2,  4,  2, 1;
  2,  8,  6, 2, 1;
  2, 16, 20, 8, 2, 1;
		

Crossrefs

Reversal of A107027.

Row sums are A107028.

Diagonal sums are A107031.

Columns include A040000, A000079, A000984, A047098.

Formula

Number triangle T(n, k)=(k-1)*C(k(n-k), n-k)-(k-2)*sum{j=0..n-k, C(k(n-k), j)}