a(n) = Sum_{k=0..floor(3*n/8)} (k+1) * binomial(k,3*n-8*k).

Terms

a(0) =1a(1) =0a(2) =0a(3) =2a(4) =0a(5) =0a(6) =3a(7) =0a(8) =4a(9) =4a(10) =0a(11) =20a(12) =5a(13) =0a(14) =60a(15) =6a(16) =7a(17) =140a(18) =7a(19) =56a(20) =280a(21) =8a(22) =252a(23) =504a(24) =19a(25) =840a(26) =840a(27) =120a(28) =2310a(29) =1320