0,2

a(n)=2*a(n-1)+a(n-2)+2*n+1; a(0)=1, a(1)=5.

(1/2) [Pell(n+3) - Pell(n+2) - 2n - 5 ], with Pell(n) = A000129(n). - Ralf Stephan, May 15 2007

a(n)=[ {(5+(7/2)*sqrt(2))(1+sqrt(2))^n - (5-(7/2)*sqrt(2))(1-sqrt(2))^n}/2*sqrt(2) ] - (2*n+5)/2.

Cf. A001333, A000129, A005409.

Sequence in context: A079094 A144952 A053220 this_sequence A099327 A004146 A071101

Adjacent sequences: A048774 A048775 A048776 this_sequence A048778 A048779 A048780

easy,nonn

Barry E. Williams