a(n) = number of n-lettered words in the alphabet {1, 2, 3} with as many occurrences of the substring (consecutive subword) [1, 2, 1] as of [2, 1, 2].
A211298
a(n) = number of n-lettered words in the alphabet {1, 2, 3} with as many occurrences of the substring (consecutive subword) [1, 2, 1] as of [2, 1, 2].
Terms
- a(0) =1a(1) =3a(2) =9a(3) =25a(4) =73a(5) =209a(6) =603a(7) =1737a(8) =5013a(9) =14479a(10) =41867a(11) =121181a(12) =351103a(13) =1018259a(14) =2955967a(15) =8589139a(16) =24980429a(17) =72717883a(18) =211867481a(19) =617816561a(20) =1803089251a(21) =5266565421a(22) =15395024547a(23) =45036636735a(24) =131848195503a(25) =386273704299
External references
- oeis: A211298