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 A235284 Number of (n+1)X(3+1) 0..3 arrays with every 2X2 subblock having its diagonal sum differing from its antidiagonal sum by 4 (constant stress 1X1 tilings) 1
 68, 104, 148, 248, 380, 680, 1108, 2072, 3548, 6824, 12148, 23768, 43580, 86120, 161428, 320792, 611228, 1218344, 2349748, 4691288, 9129980, 18243560, 35745748, 71458712, 140726108, 281386664, 556264948, 1112398808, 2205403580, 4410545000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A235289 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 3*a(n-1) +3*a(n-2) -15*a(n-3) +4*a(n-4) +18*a(n-5) -12*a(n-6) EXAMPLE Some solutions for n=4 ..3..1..3..0....0..2..0..2....1..3..2..3....1..0..1..0....3..2..3..2 ..1..3..1..2....2..0..2..0....2..0..3..0....0..3..0..3....0..3..0..3 ..3..1..3..0....0..2..0..2....0..2..1..2....3..2..3..2....2..1..2..1 ..1..3..1..2....2..0..2..0....2..0..3..0....0..3..0..3....0..3..0..3 ..3..1..3..0....0..2..0..2....0..2..1..2....3..2..3..2....2..1..2..1 CROSSREFS Sequence in context: A045268 A217776 A039540 * A250765 A048889 A111379 Adjacent sequences:  A235281 A235282 A235283 * A235285 A235286 A235287 KEYWORD nonn AUTHOR R. H. Hardin, Jan 05 2014 STATUS approved

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Last modified May 12 16:02 EDT 2021. Contains 343825 sequences. (Running on oeis4.)