a(n) = (1/3)*A289795(n).

Terms

a(0) =1a(1) =8a(2) =54a(3) =361a(4) =2420a(5) =16227a(6) =108802a(7) =729512a(8) =4891347a(9) =32796280a(10) =219897701a(11) =1474404984a(12) =9885824398a(13) =66284043461a(14) =444431768220