Main diagonal of generalized Fibonacci array A083856.

Terms

a(0) =0a(1) =1a(2) =1a(3) =4a(4) =9a(5) =41a(6) =133a(7) =673a(8) =2737a(9) =15130a(10) =72181a(11) =430739a(12) =2320825a(13) =14815529a(14) =88005541a(15) =596681296a(16) =3843559137a(17) =27515587661a(18) =189933449365