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 A210293 Half the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having at most one duplicate clockwise edge difference. 1
 112, 1578, 22212, 312704, 4402192, 61973516, 872455004, 12282307884, 172908727756, 2434186513236, 34268160178956, 482422688537636, 6791483674595260, 95609621185469444, 1345979774260696316 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 1 of A210300. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 11*a(n-1) + 42*a(n-2) + 20*a(n-3) - 18*a(n-4). Empirical g.f.: 2*x*(56 + 173*x + 75*x^2 - 72*x^3) / (1 - 11*x - 42*x^2 - 20*x^3 + 18*x^4). - Colin Barker, Jul 15 2018 EXAMPLE Some solutions for n=4: ..2..0....3..1....3..2....1..3....1..1....1..0....2..3....1..0....1..3....2..1 ..3..0....1..0....3..0....1..3....2..2....2..0....0..1....0..0....2..2....1..1 ..2..0....2..2....1..1....3..2....1..0....1..2....2..0....0..3....0..2....3..3 ..3..1....1..1....1..2....1..3....0..3....1..3....0..1....1..3....2..1....0..1 ..1..2....0..3....2..2....0..1....0..0....0..0....3..0....1..0....1..1....0..0 CROSSREFS Cf. A210300. Sequence in context: A188152 A327633 A210300 * A203915 A233884 A246895 Adjacent sequences:  A210290 A210291 A210292 * A210294 A210295 A210296 KEYWORD nonn AUTHOR R. H. Hardin, Mar 19 2012 STATUS approved

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Last modified December 5 12:24 EST 2021. Contains 349557 sequences. (Running on oeis4.)