Number of -2..2 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2).

A199903

Number of -2..2 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2).

Terms

    a(0) =1a(1) =4a(2) =12a(3) =24a(4) =82a(5) =232a(6) =654a(7) =2044a(8) =6096a(9) =18564a(10) =57500a(11) =177032a(12) =550098a(13) =1715956a(14) =5359158a(15) =16799508a(16) =52760640a(17) =165976252a(18) =523094304a(19) =1650781728a(20) =5216112586a(21) =16501009804a(22) =52252555938a(23) =165618780196a(24) =525388548976

External references