A183715 1/20 of the number of (n+1) X 6 0..4 arrays with every 2X2 subblock strictly increasing clockwise or counterclockwise with one decrease.
70, 559, 4012, 30113, 224640, 1683197, 12606120, 94463507, 707826798, 5304230928, 39748015308, 297860692491, 2232084261366, 16726639262465, 125344918169856, 939301219166473, 7038871324696794, 52747415646208987, 395274995490521924
Offset: 1
Keywords
Examples
Some solutions for 3 X 6: ..3..1..3..2..3..1....0..2..0..1..4..0....2..3..1..2..1..2....1..0..2..1..2..1 ..4..0..4..1..4..0....4..3..4..2..3..1....0..4..0..3..0..4....3..4..3..4..3..4 ..2..1..3..2..3..2....1..2..0..1..4..0....2..3..1..2..1..2....2..1..2..0..2..1 ... ...L..R..L..R..L.......R..L..R..L..R.......R..L..R..L..R.......L..R..L..R..L... ...R..L..R..L..R.......L..R..L..R..L.......L..R..L..R..L.......R..L..R..L..R...
Links
- R. H. Hardin, Table of n, a(n) for n = 1..200
Formula
Empirical: a(n)=2*a(n-1)+54*a(n-2)-2*a(n-3)-738*a(n-4)-312*a(n-5)+4078*a(n-6)+2098*a(n-7)-10802*a(n-8)-4874*a(n-9)+14854*a(n-10)+4874*a(n-11)-10802*a(n-12)-2098*a(n-13)+4078*a(n-14)+312*a(n-15)-738*a(n-16)+2*a(n-17)+54*a(n-18)-2*a(n-19)-a(n-20).
Comments