a(n) = 5*a(n-1) + 3*a(n-2), where a(0) = 0, a(1) = 3.

Terms

a(0) =0a(1) =3a(2) =15a(3) =84a(4) =465a(5) =2577a(6) =14280a(7) =79131a(8) =438495a(9) =2429868a(10) =13464825a(11) =74613729a(12) =413463120a(13) =2291156787a(14) =12696173295a(15) =70354336836a(16) =389860204065