Number of ways to color n regions arranged in a line such that consecutive regions do not have the same color.

A103293

Number of ways to color n regions arranged in a line such that consecutive regions do not have the same color.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =11a(6) =32a(7) =117a(8) =468a(9) =2152a(10) =10743a(11) =58487a(12) =340390a(13) =2110219a(14) =13830235a(15) =95475556a(16) =691543094a(17) =5240285139a(18) =41432986588a(19) =341040317063

External references