A115356 Matrix (1,x)+(x,x^2) in Riordan array notation.

1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1

Offset

0,1

Comments

Row sums are A000034. Diagonal sums are A115357. Inverse is A115358.

Links

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

Formula

Number triangle T(n, k)=if(n=k, 1, 0) OR if(n=2k+1, 1, 0).

Example

Triangle begins
1;
1, 1;
0, 0, 1;
0, 1, 0, 1;
0, 0, 0, 0, 1;
0, 0, 1, 0, 0, 1;
0, 0, 0, 0, 0, 0, 1;
0, 0, 0, 1, 0, 0, 0, 1;
0, 0, 0, 0, 0, 0, 0, 0, 1;
0, 0, 0, 0, 1, 0, 0, 0, 0, 1;

Crossrefs

Sequence in context: A229894 A256538 A074910 * A115359 A117906 A090678

Adjacent sequences: A115353 A115354 A115355 * A115357 A115358 A115359

Keyword

easy,nonn,tabl

Author

Paul Barry, Jan 21 2006

Status

approved