A207312 Number of nX3 0..2 arrays avoiding the pattern z-2 z-1 z in any row, column or nw-to-se diagonal

26, 676, 15390, 347502, 7791488, 174545777, 3908531208, 87515884741, 1959513380192, 43873997112932, 982347997376840, 21994968695108692, 492471697249839464, 11026538323840183371, 246886363177103814747

Offset

1,1

Comments

Column 3 of A207317

Links

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

Formula

Empirical: a(n) = 27*a(n-1) -43*a(n-2) -1591*a(n-3) +4195*a(n-4) +31861*a(n-5) -81210*a(n-6) -248372*a(n-7) +529289*a(n-8) +552322*a(n-9) -1158991*a(n-10) -641935*a(n-11) +1301158*a(n-12) +424638*a(n-13) -829889*a(n-14) -156675*a(n-15) +298360*a(n-16) +28115*a(n-17) -53314*a(n-18) -1015*a(n-19) +2751*a(n-20) +80*a(n-21) -64*a(n-22)

Example

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

Crossrefs

Sequence in context: A208076 A207551 A207545 * A218063 A206695 A171300

Adjacent sequences: A207309 A207310 A207311 * A207313 A207314 A207315

Keyword

nonn

Author

R. H. Hardin Feb 16 2012

Status

approved