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 A200528 Number of n X 2 0..2 arrays with every row and column running average nondecreasing rightwards and downwards. 1
 6, 20, 57, 146, 354, 825, 1873, 4169, 9144, 19825, 42590, 90815, 192457, 405760, 851740, 1781227, 3713015, 7718092, 16003641, 33111477, 68374642, 140947848, 290098848, 596244613, 1223916576, 2509450811, 5139839214, 10517282966 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A200534. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 7*a(n-1) -16*a(n-2) +6*a(n-3) +27*a(n-4) -33*a(n-5) -3*a(n-6) +24*a(n-7) -11*a(n-8) -4*a(n-9) +4*a(n-10). Empirical g.f.: x*(6 - 22*x + 13*x^2 + 31*x^3 - 38*x^4 - x^5 + 25*x^6 - 11*x^7 - 4*x^8 + 4*x^9) / ((1 - x)*(1 + x)*(1 - 2*x)^2*(1 - x - x^2)*(1 - 2*x + x^3 - x^4)). - Colin Barker, May 21 2018 EXAMPLE Some solutions for n=4: ..0..0....0..1....1..2....0..0....0..0....0..0....0..0....0..0....0..1....0..0 ..1..1....2..2....1..2....0..2....1..1....0..2....0..1....1..1....1..2....0..1 ..1..2....1..2....1..2....0..1....2..2....0..1....2..2....2..2....1..2....0..2 ..1..1....1..2....2..2....1..1....1..1....0..1....1..1....1..2....2..2....0..2 CROSSREFS Cf. A200534. Sequence in context: A048778 A048611 A292480 * A127982 A109164 A212689 Adjacent sequences: A200525 A200526 A200527 * A200529 A200530 A200531 KEYWORD nonn AUTHOR R. H. Hardin, Nov 18 2011 STATUS approved

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Last modified September 8 01:34 EDT 2024. Contains 375749 sequences. (Running on oeis4.)