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A266937
Number of 4 X n binary arrays with rows lexicographically nondecreasing and columns lexicographically nondecreasing and row sums nondecreasing and column sums nonincreasing.
1
5, 12, 20, 35, 52, 82, 115, 169, 232, 322, 426, 573, 738, 961, 1215, 1543, 1912, 2382, 2905, 3557, 4280, 5161, 6135, 7308, 8594, 10120, 11791, 13749, 15883, 18361, 21049, 24142, 27490, 31307, 35427, 40093, 45111, 50757, 56818, 63594, 70848, 78917, 87535
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) - a(n-3) - a(n-4) - a(n-5) - a(n-6) + 2*a(n-8) + 2*a(n-9) - a(n-11) - a(n-12) - a(n-13) - a(n-14) + 2*a(n-15) + a(n-16) -a(n-17).
Empirical g.f.: x*(5 + 7*x - 2*x^2 - 4*x^3 - 6*x^4 - 3*x^5 + x^6 + 9*x^7 + 12*x^8 + 2*x^9 -6*x^10 - 4*x^11 - 6*x^12 - 5*x^13 + 9*x^14 + 6*x^15 - 5*x^16) / ((1 - x)^6*(1 + x)^3*(1 + x^2)*(1 + x + x^2)*(1 + x + x^2 + x^3 + x^4)). - Colin Barker, Jan 10 2019
EXAMPLE
Some solutions for n=4:
..0..0..1..1....0..0..0..1....0..0..1..1....0..0..0..0....0..0..0..1
..1..1..0..1....0..0..1..0....1..1..0..1....0..0..0..0....0..0..1..1
..1..1..1..0....1..1..0..0....1..1..1..0....1..1..1..1....1..1..0..0
..1..1..1..0....1..1..1..0....1..1..1..1....1..1..1..1....1..1..1..0
CROSSREFS
Row 4 of A266935.
Sequence in context: A270333 A270938 A270079 * A270214 A063559 A259913
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2016
STATUS
approved