

A113126


A simple 4diagonal matrix.


3



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
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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: A115452 A039676 A242359 * A138060 A023121 A136261
Adjacent sequences: A113123 A113124 A113125 * A113127 A113128 A113129


KEYWORD

easy,nonn,tabl


AUTHOR

Paul Barry, Oct 14 2005


STATUS

approved



