Number of 0..3 arrays of length n with each element differing from at least one neighbor by something other than 1.

A221568

Number of 0..3 arrays of length n with each element differing from at least one neighbor by something other than 1.

Terms

    a(0) =0a(1) =10a(2) =26a(3) =100a(4) =342a(5) =1210a(6) =4240a(7) =14898a(8) =52306a(9) =183684a(10) =645006a(11) =2264978a(12) =7953568a(13) =27929338a(14) =98075178a(15) =344395620a(16) =1209361446a(17) =4246729738a(18) =14912591664a(19) =52366268642a(20) =183886620962a(21) =645726538244

External references