Number of ternary words of length n and having exactly one run of 0's of odd length.

Terms

a(0) =0a(1) =1a(2) =4a(3) =13a(4) =40a(5) =117a(6) =332a(7) =921a(8) =2512a(9) =6761a(10) =18004a(11) =47525a(12) =124536a(13) =324317a(14) =840092a(15) =2166065a(16) =5562272a(17) =14232273a(18) =36300196a(19) =92321085a(20) =234192584a(21) =592695109a(22) =1496810732a(23) =3772761289a(24) =9492450672a(25) =23844342073a(26) =59804611060a(27) =149787196117