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 A221751 Number of nX4 arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns 0
 1, 9, 43, 241, 1397, 7989, 45956, 264378, 1520571, 8746983, 50315631, 289432219, 1664916443, 9577180972, 55091295173, 316904423483, 1822945187570 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 4 of A221755 LINKS FORMULA Empirical: a(n) = 5*a(n-1) +5*a(n-2) +a(n-3) -27*a(n-4) -7*a(n-5) +7*a(n-6) +2*a(n-7) -a(n-8) EXAMPLE Some solutions for n=3 ..0..2..1..1....0..2..0..2....0..2..1..1....0..2..0..1....1..1..1..1 ..1..1..1..1....1..1..2..0....1..1..1..1....1..1..2..1....0..2..1..1 ..2..0..1..1....2..0..1..1....1..1..2..0....1..1..2..0....2..0..1..1 CROSSREFS Sequence in context: A281773 A220676 A110125 * A275793 A223647 A034194 Adjacent sequences:  A221748 A221749 A221750 * A221752 A221753 A221754 KEYWORD nonn AUTHOR R. H. Hardin Jan 24 2013 STATUS approved

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Last modified January 26 14:30 EST 2021. Contains 340439 sequences. (Running on oeis4.)