A154950 Riordan array (1/(1-x^4), x(1+x)/(1+x^2)).

1, 0, 1, 0, 1, 1, 0, -1, 2, 1, 1, -1, -1, 3, 1, 0, 2, -4, 0, 4, 1, 0, 2, 2, -8, 2, 5, 1, 0, -2, 8, -2, -12, 5, 6, 1, 1, -2, -2, 18, -12, -15, 9, 7, 1, 0, 3, -12, 8, 28, -29, -16, 14, 8, 1, 0, 3, 3, -32, 38, 31, -53, -14, 20, 9, 1

Offset: 0

Author

Paul Barry, Jan 17 2009

Keywords

• easy
• sign
• tabl

Comments

Row sums are A008619. Diagonal sums are A103221. Equal to A154948 times inverse of A007318.

Examples

			Triangle begins
1,
0, 1,
0, 1, 1,
0, -1, 2, 1,
1, -1, -1, 3, 1,
0, 2, -4, 0, 4, 1,
0, 2, 2, -8, 2, 5, 1,
0, -2, 8, -2, -12, 5, 6, 1,
1, -2, -2, 18, -12, -15, 9, 7, 1
		

Formula

Triangle T(n,k)=sum{i=0..n, sum{j=0..n+1, C(n+1-j,i+1)*C(i-1,j)}*(-1)^(i-k)*C(i,k)}.