Number of perfect rhythmic tilings of [0,3n-1] with triples.

Terms

a(0) =1a(1) =1a(2) =0a(3) =0a(4) =0a(5) =2a(6) =0a(7) =18a(8) =66a(9) =382a(10) =1104a(11) =4138a(12) =15324a(13) =61644a(14) =325456a(15) =2320948a(16) =17660110a(17) =148271962a(18) =1171109228a(19) =9257051746