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).
1, 4, 12, 24, 82, 232, 654, 2044, 6096, 18564, 57500, 177032, 550098, 1715956, 5359158, 16799508, 52760640, 165976252, 523094304, 1650781728, 5216112586, 16501009804, 52252555938, 165618780196, 525388548976, 1667965025692
Offset: 1
Keywords
Examples
Some solutions for n=6 ..1....0....0....1....1....1....1....1...-1...-1...-1....0....0...-2....1...-1 ..2....1...-2....2....0....0....0...-1....0....0...-2...-1...-2....2....2....0 .-2....0....2....0....2...-1...-1...-2....1....1....0....0...-1....0...-2....1 ..0....1....1...-1...-2...-2...-2....2....0....2....1....2....0...-1...-1...-1 .-1....0...-1....0...-1....0....2...-2...-1...-2....0....0....2....0...-2....0 ..0...-2....0...-2....0....2....0....2....1....0....2...-1....1....1....2....1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..200
Comments