Sum of the lengths of the drops in all ternary words of length n on {0,1,2}. The drops of a ternary word on {0,1,2} are the subwords 10,20 and 21, their lengths being the differences 1, 2 and 1, respectively.
A120908
Sum of the lengths of the drops in all ternary words of length n on {0,1,2}. The drops of a ternary word on {0,1,2} are the subwords 10,20 and 21, their lengths being the differences 1, 2 and 1, respectively.
Terms
- a(0) =0a(1) =4a(2) =24a(3) =108a(4) =432a(5) =1620a(6) =5832a(7) =20412a(8) =69984a(9) =236196a(10) =787320a(11) =2598156a(12) =8503056a(13) =27634932a(14) =89282088a(15) =286978140a(16) =918330048a(17) =2927177028a(18) =9298091736a(19) =29443957164a(20) =92980917360a(21) =292889889684a(22) =920511081864
External references
- oeis: A120908