A223253 Two-loop graph coloring a rectangular array: number of nX6 0..4 arrays where 0..4 label nodes of a graph with edges 0,1 1,2 2,0 0,3 3,4 4,0 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph

528, 22388, 1382228, 93770308, 6581646956, 465277782336, 32969186423292, 2337308796813336, 165726502883851820, 11751198778793357708, 833253057095552710328, 59084372484837842357680, 4189562192845318714550284

Offset

1,1

Comments

Column 6 of A223255

Links

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

Formula

Empirical: a(n) = 85*a(n-1) -629*a(n-2) -31878*a(n-3) +383553*a(n-4) +1511513*a(n-5) -30275140*a(n-6) +13466360*a(n-7) +868562158*a(n-8) -1847634768*a(n-9) -9913428815*a(n-10) +32760286161*a(n-11) +38433165015*a(n-12) -223138155283*a(n-13) +39999637275*a(n-14) +633199628532*a(n-15) -503848981336*a(n-16) -699539358490*a(n-17) +910162467392*a(n-18) +144242579620*a(n-19) -523191556820*a(n-20) +110096749408*a(n-21) +74380599616*a(n-22) -21347917248*a(n-23) -1345719744*a(n-24) for n>25

Example

Some solutions for n=3
..1..0..4..0..1..2....1..0..2..1..2..0....0..1..2..0..3..0....0..1..0..4..3..0
..0..3..0..4..0..1....0..2..0..2..0..3....1..2..0..3..0..4....1..0..4..3..0..4
..1..0..1..0..4..0....2..0..3..0..3..0....2..0..3..0..1..0....0..1..0..4..3..0

Crossrefs

Sequence in context: A304512 A037944 A282096 * A233103 A223244 A059465

Adjacent sequences: A223250 A223251 A223252 * A223254 A223255 A223256

Keyword

nonn

Author

R. H. Hardin Mar 18 2013

Status

approved