A177010 G.f.: ((1-q)^2+(1+q)*sqrt(1-6*q+q^2))/2.

1, -2, -3, -8, -28, -112, -484, -2200, -10364, -50144, -247684, -1243816, -6331164, -32591184, -169376484, -887465784, -4682990076, -24864759744, -132745182724, -712136879944, -3837043171100, -20755343638064, -112668274522852, -613581530620888, -3351355226348668, -18354390999804832, -100771410237846404, -554536090460808680

Offset: 0

Author

N. J. A. Sloane, Dec 08 2010

Keywords

• sign

Links

• Harris Kwong, On recurrences of Fahr and Ringel: an alternate approach, Fibonacci Quart. 48 (2010), no. 4, 363-365; see p. 364.

Crossrefs

Cf. A010683 (a closely-related g.f.)

Programs

Mathematica

CoefficientList[Series[((1 - x)^2 + (1 + x) Sqrt[1 - 6 x + x^2])/2, {x, 0, 27}], x] (* Michael De Vlieger, Oct 12 2016 *)