A249284 Number of length n+3 0..2 arrays with no four consecutive terms having the sum of any three elements equal to three times the fourth.
66, 168, 428, 1094, 2792, 7132, 18232, 46616, 119176, 304696, 779066, 1992002, 5093330, 13023126, 33299000, 85142802, 217703012, 556648464, 1423304428, 3639273226, 9305324178, 23792953554, 60836640416, 155554327024, 397739724496
Offset: 1
Keywords
Examples
Some solutions for n=9 ..1....0....2....2....1....1....0....1....1....1....0....1....1....2....2....1 ..1....0....1....0....0....1....1....0....1....0....0....1....1....0....1....0 ..0....1....0....0....2....0....2....2....2....2....0....1....2....0....0....2 ..1....0....0....0....2....1....0....2....2....0....2....2....1....0....0....2 ..0....1....2....1....0....0....0....0....1....2....2....2....2....1....1....2 ..2....0....2....0....0....0....0....1....2....1....0....0....2....0....1....0 ..0....1....2....0....0....1....2....0....2....2....2....2....1....0....0....0 ..2....1....0....1....1....1....0....1....2....1....0....2....0....1....0....2 ..0....0....0....1....2....0....2....0....0....2....2....1....0....0....2....2 ..2....0....2....1....2....1....1....0....0....1....1....2....0....2....1....2 ..2....0....2....2....1....0....2....0....1....2....2....0....2....0....2....1 ..2....2....1....2....2....0....2....1....2....0....1....0....2....0....2....0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = a(n-1) +2*a(n-2) +3*a(n-3) +7*a(n-4) +a(n-5) -6*a(n-6) -12*a(n-7) -14*a(n-8) -14*a(n-9) -7*a(n-10) +3*a(n-11) +2*a(n-12)
Comments