A183365 Number of nX3 binary arrays with no element equal to the sum mod 3 of its horizontal and vertical neighbors

2, 5, 18, 39, 108, 288, 795, 2278, 6438, 18394, 52556, 150565, 431730, 1238954, 3556322, 10210036, 29317763, 84190569, 241782416, 694380738, 1994246166, 5727497628, 16449560195, 47243891395, 135686993036, 389700996218

Offset

1,1

Comments

Column 3 of A183368

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=3*a(n-1)+a(n-3)-4*a(n-4)+4*a(n-5)-22*a(n-6)-12*a(n-7)-21*a(n-8)+22*a(n-9)-13*a(n-10)+115*a(n-11)+79*a(n-12)+116*a(n-13)-45*a(n-14)+172*a(n-15)-75*a(n-16)-54*a(n-17)-181*a(n-18)-85*a(n-19)-61*a(n-20)-11*a(n-21)-158*a(n-22)+80*a(n-23)+157*a(n-24)+215*a(n-25)-78*a(n-26)-211*a(n-27)-196*a(n-28)-51*a(n-29)+44*a(n-30)+81*a(n-31)+64*a(n-32)+13*a(n-33)-13*a(n-34)-12*a(n-35)-7*a(n-36)-a(n-37)+a(n-38)+a(n-39)

Example

Some solutions for 5X3
..1..0..1....1..1..1....0..1..1....0..0..0....1..1..0....0..1..1....1..1..0
..0..0..0....1..1..1....1..1..1....1..1..1....1..1..0....0..1..1....1..1..0
..1..1..0....0..0..0....1..0..1....1..1..1....1..1..0....0..1..1....0..0..1
..1..1..0....0..0..1....1..1..1....0..0..0....0..1..1....0..1..1....1..0..0
..0..0..1....1..0..0....1..1..0....0..1..0....0..1..1....1..0..0....0..1..0

Crossrefs

Sequence in context: A226141 A355515 A048221 * A295905 A056296 A293964

Adjacent sequences: A183362 A183363 A183364 * A183366 A183367 A183368

Keyword

nonn

Author

R. H. Hardin Jan 04 2011

Status

approved