A124731 Triangle, row sums = powers of 3, companion to A124730.

1, 2, 1, 4, 3, 2, 8, 7, 10, 2, 16, 15, 34, 12, 4, 32, 31, 98, 46, 32, 4, 64, 63, 258, 144, 156, 36, 8, 128, 127, 642, 402, 600, 192, 88, 8, 256, 255, 1538, 1044, 2004, 792, 560, 96, 16

Offset

0,2

Comments

In A124730, the diagonals are switched. Row sums are powers of 3 in both triangles.

Links

Table of n, a(n) for n=0..44.

Formula

Let M = the infinite bidiagonal matrix with (2,1,2,1...) in the main diagonal and (1,2,1,2...) in the subdiagonal. Extracting finite n X n matrices of this form, we take M^n * [1,0,0,0...].

Example

Row 2 = (4, 3, 2) since (using the 3 X 3 matrix m = [2,0,0; 1,1,0; 0,2,2]), m^2 * [1,0,0] = [4,3,2].
First few rows of the triangle are:
1;
2, 1;
4, 3, 2;
8, 7, 10, 2;
16, 15, 34, 12, 4;
32, 31, 98, 46, 32, 4;
64, 63, 258, 144, 156, 36, 8;
...

Crossrefs

Cf. A124730, A124732.

Sequence in context: A144333 A126136 A140169 * A210658 A143122 A093067

Adjacent sequences: A124728 A124729 A124730 * A124732 A124733 A124734

Keyword

nonn,tabl

Author

Gary W. Adamson & Roger L. Bagula, Nov 05 2006

Status

approved