A117362 Riordan array (1-2x,x(1-x)).

1, -2, 1, 0, -3, 1, 0, 2, -4, 1, 0, 0, 5, -5, 1, 0, 0, -2, 9, -6, 1, 0, 0, 0, -7, 14, -7, 1, 0, 0, 0, 2, -16, 20, -8, 1, 0, 0, 0, 0, 9, -30, 27, -9, 1, 0, 0, 0, 0, -2, 25, -50, 35, -10, 1, 0, 0, 0, 0, 0, -11, 55, -77, 44, -11, 1

Offset

0,2

Comments

A signed version of A113214. Inverse of A092392. Row sums are A100051(n+1) with g.f. (1-2x)/(1-x+x^2). Diagonal sums are A117363.

Links

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

Formula

Number triangle T(n,k)=(-1)^(n-k)(C(k,n-k)+2*C(k, n-k-1))

Example

Triangle begins
1,
-2, 1,
0, -3, 1,
0, 2, -4, 1,
0, 0, 5, -5, 1,
0, 0, -2, 9, -6, 1,
0, 0, 0, -7, 14, -7, 1,
0, 0, 0, 2, -16, 20, -8, 1

Crossrefs

Sequence in context: A202452 A376789 A127013 * A247492 A113214 A280494

Adjacent sequences: A117359 A117360 A117361 * A117363 A117364 A117365

Keyword

easy,sign,tabl

Author

Paul Barry, Mar 10 2006

Status

approved