0,2

a(0)=0, a(1)=4 and a(n)=18*a(n-1) - a(n-2) + 8.

a(n)=-(1/2)+(1/4)*[9-4*sqrt(5)]^n+(1/4)*[9+4*sqrt(5)]^n, with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Oct 07 2008]

Cf. A007654.

Sequence in context: A054322 A114488 A055787 this_sequence A012127 A057875 A012824

Adjacent sequences: A132581 A132582 A132583 this_sequence A132585 A132586 A132587

nonn

Mohamed Bouhamida (bhmd95(AT)yahoo.fr), Nov 14 2007