A207984 Number of nX3 0..2 arrays avoiding the pattern z z+1 z horizontally and z z-1 z vertically

25, 625, 12468, 244325, 4827482, 95527856, 1889730415, 37378616643, 739356161720, 14624722337624, 289281704602147, 5722081129193560, 113184543292907805, 2238825594019420023, 44284668170957511026

Offset

1,1

Comments

Column 3 of A207989

Links

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

Formula

Empirical: a(n) = 19*a(n-1) -82*a(n-2) +1805*a(n-3) +220*a(n-4) +37871*a(n-5) +129800*a(n-6) -405005*a(n-7) +1172158*a(n-8) -6167316*a(n-9) -43541834*a(n-10) +69300150*a(n-11) +55466198*a(n-12) -255109849*a(n-13) +3952679917*a(n-14) +2475383625*a(n-15) -32889586196*a(n-16) -23614518648*a(n-17) +104745099284*a(n-18) +94890799808*a(n-19) -103200497427*a(n-20) -139161370343*a(n-21) -182731979141*a(n-22) -90465024043*a(n-23) +437487172472*a(n-24) +434721978924*a(n-25) +49576922630*a(n-26) -130621709988*a(n-27) -631546486515*a(n-28) -525937727288*a(n-29) +61389004142*a(n-30) +236882586444*a(n-31) +527121385584*a(n-32) +386245192022*a(n-33) +8869421132*a(n-34) -116274513050*a(n-35) -257296296124*a(n-36) -186082116614*a(n-37) -68790374049*a(n-38) +112956022*a(n-39) +45338030679*a(n-40) +44581181721*a(n-41) +21926766670*a(n-42) +10110542117*a(n-43) -2733155250*a(n-44) -3935285362*a(n-45) -3715462652*a(n-46) -2045132864*a(n-47) -803304695*a(n-48) -153906529*a(n-49) +38294902*a(n-50) +105081309*a(n-51) +51670795*a(n-52) +37874190*a(n-53) +11725070*a(n-54) +6420274*a(n-55) +1438607*a(n-56) +659455*a(n-57) +105682*a(n-58) +42329*a(n-59) +4407*a(n-60) +1587*a(n-61) +81*a(n-62) +27*a(n-63)

Example

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

Crossrefs

Sequence in context: A206952 A206729 A207353 * A207196 A207216 A171299

Adjacent sequences: A207981 A207982 A207983 * A207985 A207986 A207987

Keyword

nonn

Author

R. H. Hardin Feb 22 2012

Status

approved