0,2

G.f.: (1+8*x-9*x^2+8*x^3)/(1-18*x^2+x^4). a(n)=18*a(n-2)-a(n-4).

Cf. A041143.

Sequence in context: A116249 A165467 A041141 this_sequence A041605 A115073 A042393

Adjacent sequences: A041139 A041140 A041141 this_sequence A041143 A041144 A041145

nonn,cofr,easy

N. J. A. Sloane (njas(AT)research.att.com).