a(n) = a(n-1) + 7*a(n-2), a(0)=0, a(1)=1.

Terms

a(0) =0a(1) =1a(2) =1a(3) =8a(4) =15a(5) =71a(6) =176a(7) =673a(8) =1905a(9) =6616a(10) =19951a(11) =66263a(12) =205920a(13) =669761a(14) =2111201a(15) =6799528a(16) =21577935a(17) =69174631a(18) =220220176a(19) =704442593a(20) =2245983825a(21) =7177081976a(22) =22898968751a(23) =73138542583a(24) =233431323840a(25) =745401121921