a(n)=a(n-1)+6a(n-2), n>2.

Terms

a(0) =1a(1) =5a(2) =14a(3) =44a(4) =128a(5) =392a(6) =1160a(7) =3512a(8) =10472a(9) =31544a(10) =94376a(11) =283640a(12) =849896a(13) =2551736a(14) =7651112a(15) =22961528a(16) =68868200a(17) =206637368a(18) =619846568a(19) =1859670776a(20) =5578750184a(21) =16736774840a(22) =50209275944a(23) =150629924984a(24) =451885580648