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 A253428 Number of (n+1)X(n+1) 0..1 arrays with every 2X2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally 0
 16, 58, 85, 156, 300, 588, 1164, 2316, 4620, 9228, 18444, 36876, 73740, 147468, 294924, 589836, 1179660, 2359308, 4718604, 9437196, 18874380, 37748748, 75497484, 150994956, 301989900, 603979788 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Diagonal of A253435 LINKS FORMULA Empirical: a(n) = 3*a(n-1) -2*a(n-2) for n>5 Empirical: a(n) = 9*2^n + 12 for n>3 EXAMPLE Some solutions for n=4 ..0..1..1..1..0....1..1..1..1..1....0..0..1..0..1....0..1..1..1..1 ..1..1..1..1..0....1..1..1..1..1....1..0..1..0..1....1..1..1..1..1 ..1..1..1..1..0....0..0..0..0..0....1..0..1..0..1....1..1..1..1..1 ..1..1..1..1..0....0..0..0..0..0....1..0..1..0..1....0..0..0..0..0 ..1..1..1..1..1....1..1..1..1..1....1..0..1..0..1....0..0..0..0..0 CROSSREFS Sequence in context: A235449 A235736 A235517 * A005905 A177890 A225922 Adjacent sequences:  A253425 A253426 A253427 * A253429 A253430 A253431 KEYWORD nonn AUTHOR R. H. Hardin, Dec 31 2014 STATUS approved

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Last modified October 21 21:50 EDT 2018. Contains 316429 sequences. (Running on oeis4.)