Number of edges in the n-Pell graph.

Terms

a(0) =0a(1) =1a(2) =5a(3) =18a(4) =58a(5) =175a(6) =507a(7) =1428a(8) =3940a(9) =10701a(10) =28705a(11) =76230a(12) =200766a(13) =525083a(14) =1365175a(15) =3531240a(16) =9093512a(17) =23325785a(18) =59625981a(19) =151947066a(20) =386139650a(21) =978834759a(22) =2475645491a(23) =6248406780a(24) =15740857452a(25) =39585199525a(26) =99389810585a(27) =249177006702a(28) =623846750086