A113678 Sequence array for A078008.

1, 0, 1, 2, 0, 1, 2, 2, 0, 1, 6, 2, 2, 0, 1, 10, 6, 2, 2, 0, 1, 22, 10, 6, 2, 2, 0, 1, 42, 22, 10, 6, 2, 2, 0, 1, 86, 42, 22, 10, 6, 2, 2, 0, 1, 170, 86, 42, 22, 10, 6, 2, 2, 0, 1, 342, 170, 86, 42, 22, 10, 6, 2, 2, 0, 1, 682, 342, 170, 86, 42, 22, 10, 6, 2, 2, 0, 1, 1366, 682, 342, 170, 86

Offset

0,4

Comments

Row sums are A001045(n+1). Diagonal sums are A053088. Inverse is A113680.

Links

Table of n, a(n) for n=0..82.

Formula

Riordan array ((1-x)/(1-x-2x^2), x); Number triangle T(n, k)=if(k<=n, (2^(n-k)+2(-1)^(n-k))/3, 0); T(n, k)=sum{i=0..n, C(n-i, k)C(k, n-i)(2^i+2(-1)^i)/3}.

Example

Triangle begins
1;
0, 1;
2, 0, 1;
2, 2, 0, 1;
6, 2, 2, 0, 1;
10, 6, 2, 2, 0, 1;
22, 10, 6, 2, 2, 0, 1;

Crossrefs

Sequence in context: A118401 A354786 A147767 * A305436 A328708 A299480

Adjacent sequences: A113675 A113676 A113677 * A113679 A113680 A113681

Keyword

easy,nonn,tabl

Author

Paul Barry, Nov 04 2005

Status

approved