A110168 - OEIS

A110168

Riordan array ((1-x^2)/(1+3x+x^2),x/(1+3x+x^2)).

1, -3, 1, 7, -6, 1, -18, 24, -9, 1, 47, -84, 50, -12, 1, -123, 275, -225, 85, -15, 1, 322, -864, 900, -468, 129, -18, 1, -843, 2639, -3339, 2219, -840, 182, -21, 1, 2207, -7896, 11756, -9528, 4610, -1368, 244, -24, 1, -5778, 23256, -39825, 38121, -22518, 8532, -2079, 315, -27, 1, 15127, -67650, 130975

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OFFSET

0,2

COMMENTS

Inverse of A110165. Row sums are 1,-2,2,-2,... with g.f. (1-x)/(1+x). Diagonal sums are (-1)^n*A080923. Product of A110162 and inverse binomial transform (1/(1+x),x/(1+x)).

LINKS

Table of n, a(n) for n=0..57.

FORMULA

T(n,k) = T(n-1,k-1) - 3*T(n-1,k) - T(n-2,k), T(0,0) = T(1,1) = T(2,2) = 1, T(1,0) = -3, T(2,0) = 7, T(2,1) = -6, T(n,k) = 0 if k<0 or if k>n. - Philippe Deléham, Jan 22 2014

EXAMPLE

Rows begin

-3,1;

7,-6,1;

-18,24,-9,1;

47,-84,50,-12,1;

-123,275,-225,85,-15,1;

CROSSREFS

Sequence in context: A372118 A321163 A054458 * A323663 A355928 A205298

Adjacent sequences: A110165 A110166 A110167 * A110169 A110170 A110171

KEYWORD

easy,sign,tabl

AUTHOR

Paul Barry, Jul 14 2005

STATUS

approved