0,2

a(n) = 6*a(n-2) - a(n-4). a(2n) = a(2n-1)+a(2n-2), a(2n+1)=4*a(2n)+a(2n-1).

G.f.: (1+2*x-3*x^2+2*x^3)/(1-6*x^2+x^4).

Cf. A041011. Also A001333(2n)=A041010(2n), A001333(2n+1)=A041010(2n+1)/2.

Sequence in context: A042367 A100341 A041869 this_sequence A041733 A107083 A081615

Adjacent sequences: A041007 A041008 A041009 this_sequence A041011 A041012 A041013

nonn,cofr,easy

njas

Entry improved by Michael Somos