A118406 Unsigned row sums of triangle A118404.

1, 2, 2, 4, 4, 8, 14, 28, 52, 104, 206, 412, 820, 1640, 3278, 6556, 13108, 26216, 52430, 104860, 209716, 419432, 838862, 1677724, 3355444, 6710888, 13421774, 26843548, 53687092, 107374184, 214748366, 429496732, 858993460, 1717986920, 3435973838

Offset: 0

Author

Paul D. Hanna, Apr 27 2006

Keywords

• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (2,0,0,1,-2).

Crossrefs

Cf. A118404, A118405.

Programs

Mathematica

CoefficientList[Series[(1-2x^2-5x^4)/(1-x^4)/(1-2x),{x,0,40}],x] (* or *) LinearRecurrence[{2,0,0,1,-2},{1,2,2,4,4},40] (* Harvey P. Dale, Jul 29 2021 *)

PARI

{a(n)=polcoeff((1 - 2*x^2 - 5*x^4)/(1-x^4)/(1-2*x+x*O(x^n)),n,x)}

Formula

G.f.: A(x) = (1 - 2*x^2 - 5*x^4)/(1-x^4)/(1-2*x).