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 A206660 Number of (n+1) X (n+1) 0..2 arrays with every 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward and upward neighbors. 0
 81, 2691, 166605, 25229685, 10351091007, 11143560422013, 30831727837091925, 217363460829124577235, 3903604149526204562445729 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Diagonal of A206668. LINKS Table of n, a(n) for n=1..9. EXAMPLE Some solutions for n=4: ..1..2..0..2..1....2..1..0..2..1....1..2..1..2..1....2..1..2..2..2 ..0..0..0..0..0....2..0..1..0..2....1..0..1..0..0....2..2..2..1..1 ..1..1..1..2..1....0..2..0..2..1....1..2..1..2..1....1..1..1..1..2 ..2..2..0..2..1....1..0..2..1..2....0..0..0..2..0....0..1..2..2..2 ..0..1..0..2..1....2..1..0..2..0....1..2..1..2..1....0..1..2..1..2 CROSSREFS Sequence in context: A210128 A297084 A018223 * A253525 A253741 A253516 Adjacent sequences: A206657 A206658 A206659 * A206661 A206662 A206663 KEYWORD nonn AUTHOR R. H. Hardin, Feb 11 2012 STATUS approved

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Last modified August 10 12:12 EDT 2024. Contains 375056 sequences. (Running on oeis4.)