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A206271 Number of (n+1) X 3 0..2 arrays with no 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward or upward neighbors. 1
306, 972, 3168, 11205, 35922, 123357, 408198, 1376754, 4572942, 15438600, 51367338, 172747923, 576448980, 1935886518, 6465571452, 21695411226, 72514916274, 243164479179, 813186470136, 2725748659476, 9118451550024 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 2 of A206277.
LINKS
FORMULA
Empirical: a(n) = 8*a(n-2) +28*a(n-4) +36*a(n-5) -18*a(n-6) +78*a(n-7) -490*a(n-8) +298*a(n-9) +86*a(n-10) -854*a(n-11) +1669*a(n-12) -524*a(n-13) -872*a(n-14) +648*a(n-15) +140*a(n-16) -302*a(n-17) +10*a(n-18) +76*a(n-19) +8*a(n-20) -16*a(n-21) +8*a(n-22) for n>24.
EXAMPLE
Some solutions for n=4:
..2..0..2....1..2..0....0..1..1....0..2..2....2..1..0....0..0..0....1..2..1
..1..1..0....1..0..1....2..1..1....0..1..2....2..2..1....1..2..0....0..1..1
..1..1..0....2..1..1....0..2..2....0..0..1....2..2..2....1..2..1....0..0..2
..1..2..1....2..1..1....0..2..2....0..0..1....0..2..2....0..0..2....2..1..0
..0..1..1....0..2..1....1..0..2....2..1..2....2..0..2....0..0..1....1..0..0
CROSSREFS
Sequence in context: A005951 A294596 A294710 * A236012 A158589 A030030
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 05 2012
STATUS
approved

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Last modified July 15 00:37 EDT 2024. Contains 374323 sequences. (Running on oeis4.)