A233128 Number of nX7 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs)

528, 1495040, 4653056000, 14800557965312, 47441169369530368, 152534173898504142848, 491056502853059022422016, 1581710916068322391195910144, 5095889238903796606027591319552

Offset

1,1

Comments

Column 7 of A233129

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 7168*a(n-1) -19070976*a(n-2) +26086473728*a(n-3) -21081846972416*a(n-4) +10809917287956480*a(n-5) -3649692508960587776*a(n-6) +824336623994081902592*a(n-7) -124561639357723747287040*a(n-8) +12414326720213201465638912*a(n-9) -792885332473813431379558400*a(n-10) +31062140009178282014900486144*a(n-11) -704387882353381376417601683456*a(n-12) +8398185226512019784915658735616*a(n-13) -40564819207303340847894502572032*a(n-14)

Example

Some solutions for n=1
..0..1..0..4..5..4..5....0..1..0..4..5..1..5....0..1..0..2..0..4..2

Crossrefs

Sequence in context: A225834 A263909 A233173 * A233255 A204684 A205160

Adjacent sequences: A233125 A233126 A233127 * A233129 A233130 A233131

Keyword

nonn

Author

R. H. Hardin, Dec 04 2013

Status

approved