a(n) = F(n+1)*F(n+2) - F(n), where F = A000045 (Fibonacci numbers).

Terms

a(0) =1a(1) =5a(2) =13a(3) =37a(4) =99a(5) =265a(6) =701a(7) =1849a(8) =4861a(9) =12761a(10) =33463a(11) =87697a(12) =229737a(13) =601693a(14) =1575629a(15) =4125661a(16) =10802107a(17) =28281881a(18) =74045509a(19) =193857841a(20) =507533181a(21) =1328750065a(22) =3478730543a(23) =9107463457a(24) =23843695249a(25) =62423679605a(26) =163427436301a(27) =427858779349