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

1,6

Links

Table of n, a(n) for n=1..63.

Example

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.

Sequence in context: A057277 A258712 A238094 * A295633 A159778 A243278

Adjacent sequences: A140731 A140732 A140733 * A140735 A140736 A140737

Keyword

nonn,tabl

Author

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

Status

approved