A122440 Riordan array ((3-sqrt(1+8x))/2, (sqrt(1+8x)-1)/4).

1, -2, 1, 4, -4, 1, -16, 16, -6, 1, 80, -80, 32, -8, 1, -448, 448, -184, 52, -10, 1, 2688, -2688, 1120, -336, 76, -12, 1, -16896, 16896, -7104, 2208, -544, 104, -14, 1, 109824

Offset

0,2

Comments

Inverse of A122438. Row sums are A122441.

Links

Table of n, a(n) for n=0..36.

Example

Triangle begins
1,
-2, 1,
4, -4, 1,
-16, 16, -6, 1,
80, -80, 32, -8, 1,
-448, 448, -184, 52, -10, 1,
2688, -2688, 1120, -336, 76, -12, 1

Crossrefs

Sequence in context: A097761 A200756 A108556 * A046943 A107728 A128250

Adjacent sequences: A122437 A122438 A122439 * A122441 A122442 A122443

Keyword

easy,sign,tabl

Author

Paul Barry, Sep 05 2006

Status

approved