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

A199904

Number of -3..3 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) =24a(3) =72a(4) =256a(5) =1312a(6) =5206a(7) =21208a(8) =97668a(9) =422052a(10) =1819620a(11) =8158144a(12) =36110122a(13) =159422584a(14) =712790438a(15) =3182921756a(16) =14206099012a(17) =63688577860a(18) =285783359204

External references