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

0,9

Comments

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

Links

Table of n, a(n) for n=0..65.

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)}.

Example

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

Crossrefs

Sequence in context: A257463 A293483 A125761 * A260089 A296240 A158464

Adjacent sequences: A154947 A154948 A154949 * A154951 A154952 A154953

Keyword

easy,sign,tabl

Author

Paul Barry, Jan 17 2009

Status

approved