A113126 A simple 4-diagonal matrix.

1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 0, 2, 3, 4, 5, 0, 0, 3, 4, 5, 6, 0, 0, 0, 4, 5, 6, 7, 0, 0, 0, 0, 5, 6, 7, 8, 0, 0, 0, 0, 0, 6, 7, 8, 9, 0, 0, 0, 0, 0, 0, 7, 8, 9, 10, 0, 0, 0, 0, 0, 0, 0, 8, 9, 10, 11, 0, 0, 0, 0, 0, 0, 0, 0, 9, 10, 11, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 11, 12, 13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

0,3

Comments

Row sums are A113127. Diagonal sums are A109613. Diagonals are A000027.

Links

Table of n, a(n) for n=0..100.

Formula

Number triangle where column k has g.f. (1+x+x^2+x^3)(k+1)x^k.

Example

Triangle begins
1;
1,2;
1,2,3;
1,2,3,4;
0,2,3,4,5;
0,0,3,4,5,6;
0,0,0,4,5,6,7;
0,0,0,0,5,6,7,8;
0,0,0,0,0,6,7,8,9;

Crossrefs

Cf. A113125.

Sequence in context: A039676 A242359 A368485 * A348043 A138060 A023121

Adjacent sequences: A113123 A113124 A113125 * A113127 A113128 A113129

Keyword

easy,nonn,tabl

Author

Paul Barry, Oct 14 2005

Status

approved