A140767 Triangle read by rows, X^n * [1,1,0,0,0,...] where X = a tridiagonal matrix with (1,1,1,...) in the main and subdiagonals and (1,0,1,0,1,...) in the subsubdiagonal.

1, 1, 1, 2, 2, 1, 3, 5, 2, 2, 1, 4, 9, 7, 9, 2, 2, 1, 5, 14, 16, 25, 11, 13, 2, 2, 1, 6, 20, 30, 55, 36, 49, 15, 17, 2, 2, 1, 7, 27, 50, 105, 91, 140, 64, 81, 19, 21, 2, 2, 1, 8, 35, 77, 182, 196, 336, 204, 285, 100, 121, 23, 25, 2, 2

Offset

0,4

Comments

Row sums = odd-indexed Fibonacci numbers starting (2, 5, 13, 34, 89, ...).

Links

Table of n, a(n) for n=0..64.

Example

First few rows of the triangle are:
  1, 1;
  1, 2,  2;
  1, 3,  5,  2,   2;
  1, 4,  9,  7,   9,  2,   2;
  1, 5, 14, 16,  25, 11,  13,  2,  2;
  1, 6, 20, 30,  55, 36,  49, 15, 17,  2,  2;
  1, 7, 27, 50, 105, 91, 140, 64, 81, 19, 21, 2, 2;
  ...

Crossrefs

Sequence in context: A046752 A086350 A239830 * A060850 A208336 A038137

Adjacent sequences: A140764 A140765 A140766 * A140768 A140769 A140770

Keyword

nonn,tabf

Author

Gary W. Adamson & Roger L. Bagula, May 28 2008

Status

approved