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 A223882 Number of n X 2 0..2 arrays with row sums unimodal and column sums inverted unimodal. 1

%I

%S 9,81,564,3298,17048,80412,353485,1469903,5845411,22414731,83409546,

%T 302722400,1075880306,3756503134,12919764299,43865509013,147290172421,

%U 489846413077,1615582428816,5289834522606,17210293320924,55679866275376

%N Number of n X 2 0..2 arrays with row sums unimodal and column sums inverted unimodal.

%C Column 2 of A223885.

%H R. H. Hardin, <a href="/A223882/b223882.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 17*a(n-1) - 126*a(n-2) + 534*a(n-3) - 1425*a(n-4) + 2481*a(n-5) - 2816*a(n-6) + 2008*a(n-7) - 816*a(n-8) + 144*a(n-9).

%F Empirical g.f.: x*(9 - 72*x + 321*x^2 - 890*x^3 + 1617*x^4 - 1936*x^5 + 1480*x^6 - 672*x^7 + 144*x^8) / ((1 - x)^3*(1 - 2*x)^4*(1 - 3*x)^2). - _Colin Barker_, Aug 24 2018

%e Some examples for n=3:

%e ..0..1....0..0....1..1....0..1....0..0....1..2....0..0....0..1....0..2....2..2

%e ..0..2....1..2....2..2....2..0....1..0....2..2....0..0....0..2....2..2....0..2

%e ..2..0....2..2....0..0....1..1....1..2....0..2....0..0....1..1....1..1....0..1

%Y Cf. A223885.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 28 2013

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Last modified January 27 15:42 EST 2022. Contains 350607 sequences. (Running on oeis4.)