a(n) is the number of words of length n on the alphabet {0,1,2} with the number of 0's plus the number of 1's congruent to the number of 2's modulo 3.

A334656

a(n) is the number of words of length n on the alphabet {0,1,2} with the number of 0's plus the number of 1's congruent to the number of 2's modulo 3.

Terms

    a(0) =1a(1) =0a(2) =4a(3) =9a(4) =24a(5) =90a(6) =225a(7) =756a(8) =2160a(9) =6561a(10) =19764a(11) =58806a(12) =177633a(13) =530712a(14) =1595052a(15) =4782969a(16) =14346720a(17) =43053282a(18) =129127041a(19) =387440172a(20) =1162241784a(21) =3486784401a(22) =10460412252a(23) =31380882462a(24) =94143533121a(25) =282429005040a(26) =847289140884

External references