a(n) = Sum_{k=0..floor(3*n/8)} binomial(k+2,3*n-8*k).

Terms

a(0) =1a(1) =0a(2) =0a(3) =3a(4) =0a(5) =0a(6) =6a(7) =0a(8) =1a(9) =10a(10) =0a(11) =6a(12) =15a(13) =0a(14) =21a(15) =21a(16) =1a(17) =56a(18) =28a(19) =9a(20) =126a(21) =36a(22) =45a(23) =252a(24) =46a(25) =165a(26) =462a(27) =67a(28) =495a(29) =792