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A186476 Number of (n+1)X4 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors 1
1098, 701, 4686, 4810, 20224, 21760, 82632, 101108, 344804, 465884, 1445243, 2112183, 6085048, 9483898, 25738600, 42272077, 109291705, 187344208, 465619270, 826593388, 1989294067, 3634249423, 8519209648, 15933856258, 36556619512 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 3 of A186482
LINKS
FORMULA
Empirical: a(n)=2*a(n-1)+2*a(n-2)-6*a(n-3)+6*a(n-4)-3*a(n-5) for n>14
EXAMPLE
Some solutions for 3X4
..2..0..1..0....2..2..2..0....0..0..1..1....0..3..0..2....0..1..0..3
..0..2..0..1....0..0..0..2....0..0..0..1....2..0..3..0....0..0..1..0
..2..0..2..2....0..0..0..2....1..0..0..0....0..2..0..3....0..0..0..1
CROSSREFS
Sequence in context: A234722 A160370 A123366 * A096926 A249287 A252418
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 22 2011
STATUS
approved

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Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)