0,2

a(n)=2*a(n-1)+a(n-2)+9; a(0)=1, a(1)=11.

a(n)=[ {(10+(11/2)*sqrt(2))(1+sqrt(2))^n - (10-(11/2)*sqrt(2))(1-sqrt(2))^n}/ 2*sqrt(2) ]-9/2.

Cf. A001333, A000129, A048696, A048697.

Sequence in context: A045982 A059134 A007790 this_sequence A056123 A006655 A018956

Adjacent sequences: A048770 A048771 A048772 this_sequence A048774 A048775 A048776

easy,nice,nonn

Barry E. Williams