First subdiagonal of generalized Fibonacci array A083856.

Terms

a(0) =0a(1) =1a(2) =1a(3) =5a(4) =11a(5) =55a(6) =176a(7) =937a(8) =3781a(9) =21571a(10) =102455a(11) =624493a(12) =3356640a(13) =21752431a(14) =129055681a(15) =884773585a(16) =5696734715a(17) =41129090011a(18) =283908657880