A167684 Triangle read by rows given by [2,-1,1,-2,0,0,0,0,0,0,0,...] DELTA [1,0,1,-1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938.

1, 2, 1, 2, 3, 1, 0, 2, 3, 1, 0, 0, 2, 3, 1, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 1

Offset

0,2

Links

Table of n, a(n) for n=0..104.

Formula

G.f.: (1+2*x+2*x^2+x^2*y)/(1-x*y). - Philippe Deléham, Nov 09 2013

T(n,k) = T(n-1,k-1) for n>2, T(0,0) = T(1,1) = T(2,2) = 1, T(1,0) = T(2,0) = 2, T(2,1) = 3, T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Nov 09 2013

Example

Triangle begins :
1 ;
2,1 ;
2,3,1 ;
0,2,3,1 ;
0,0,2,3,1 ;
0,0,0,2,3,1 ;
0,0,0,0,2,3,1 ; ...

Crossrefs

Sequence in context: A249777 A289065 A132815 * A094646 A124448 A143343

Adjacent sequences: A167681 A167682 A167683 * A167685 A167686 A167687

Keyword

nonn,tabl

Author

Philippe Deléham, Nov 09 2009

Status

approved