The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 60th year, we have over 367,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A233163 Number of n X 3 0..7 arrays with no element x(i,j) adjacent to itself or value 7-x(i,j) horizontally, diagonally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 3 4 5 and 6, 2 appearing before 3 4 and 5, and 3 appearing before 4 in row major order (unlabelled 8-colorings with no clashing color pairs). 1
 3, 8, 96, 1280, 18432, 278528, 4325376, 68157440, 1082130432, 17246978048, 275414777856, 4402341478400, 70403103916032, 1126174784749568, 18016597532737536, 288247968337756160, 4611826755915743232 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 24*a(n-1) - 128*a(n-2) for n>3. Conjectures from Colin Barker, Oct 09 2018: (Start) G.f.: x*(3 - 64*x + 288*x^2) / ((1 - 8*x)*(1 - 16*x)). a(n) = 8^(n-2) * (2^n+4) for n>1. (End) EXAMPLE Some solutions for n=5: ..0..1..2....0..1..7....0..1..0....0..1..7....0..1..0....0..1..2....0..1..7 ..5..3..7....2..3..2....2..3..5....2..3..2....2..3..2....5..3..7....2..3..2 ..0..6..2....6..0..1....1..0..1....0..6..7....0..1..7....7..1..5....0..1..0 ..5..4..0....3..2..3....3..5..4....4..5..3....3..5..4....2..4..7....4..2..3 ..7..6..5....1..0..1....0..1..7....1..7..6....7..6..7....0..6..5....6..0..6 CROSSREFS Column 3 of A233168. Sequence in context: A266671 A069703 A114737 * A281709 A099296 A066619 Adjacent sequences: A233160 A233161 A233162 * A233164 A233165 A233166 KEYWORD nonn AUTHOR R. H. Hardin, Dec 05 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 7 04:15 EST 2023. Contains 367629 sequences. (Running on oeis4.)