A140734 Triangle read by rows, X^n * [1,0,0,0,...]; where X = a tridiagonal matrix with (1,1,1,...) in the main and subsubdiagonals and (1,2,3,...) in the subdiagonal.

1, 1, 1, 1, 1, 2, 4, 4, 1, 1, 3, 9, 18, 21, 9, 1, 1, 4, 16, 48, 102, 132, 76, 16, 1, 1, 5, 25, 100, 310, 690, 970, 680, 205, 25, 1, 1, 6, 36, 180, 735, 2340, 5420, 8160, 2550, 456, 36, 1, 1, 7, 49, 294, 1491, 6195, 20195, 48440, 778315, 70245, 32571, 7602, 889, 49, 1

Offset: 1

Author

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

Keywords

• nonn
• tabl

Examples

			First few rows of the triangle:
  1;
  1, 1,  1;
  1, 2,  4,   4,    1;
  1, 3,  9,  18,   21,    9,     1;
  1, 4, 16,  48,  102,  132,    76,    16,     1;
  1, 5, 25, 100,  310,  690,   970,   680,   205,    25,     1;
  1, 6, 36, 180,  735, 2340,  5420,  8160,  2550,   456,    36,    1;
  1, 7, 49, 294, 1491, 6195, 20195, 48440, 77315, 70245, 32571, 7602, 889, 49, 1;
  ...
		

Crossrefs

Cf. A140733, A140735.