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%I #4 Mar 30 2013 08:10:48
%S 20,400,5029,44803,308470,1738756,8350154,35158856,132595894,
%T 455284536,1441678804,4253578398,11791889562,30929283640,77204065141,
%U 184304047745,422556706314,933834642586,1995549087157,4134881948947,8327774224280
%N Number of 3Xn 0..3 arrays with rows unimodal and columns nondecreasing
%C Row 3 of A223987
%H R. H. Hardin, <a href="/A223988/b223988.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = (1/3629463552000)*n^18 + (1/44808192000)*n^17 + (10403/10461394944000)*n^16 + (10537/373621248000)*n^15 + (2915977/5230697472000)*n^14 + (6071381/747242496000)*n^13 + (748919/8211456000)*n^12 + (23111713/28740096000)*n^11 + (409218107/73156608000)*n^10 + (320706361/10450944000)*n^9 + (107018740483/804722688000)*n^8 + (467745209/1026432000)*n^7 + (10942630223/8895744000)*n^6 + (239853259979/93405312000)*n^5 + (882554800469/217945728000)*n^4 + (6093492161/1297296000)*n^3 + (4200944633/1029188160)*n^2 + (1784593/1021020)*n + 1
%e Some solutions for n=3
%e ..0..2..2....0..0..3....0..1..1....1..2..0....2..1..1....0..1..0....0..1..1
%e ..0..2..2....0..0..3....1..1..3....1..2..1....2..2..1....1..2..0....1..2..1
%e ..3..2..2....2..3..3....3..3..3....1..2..1....3..3..2....3..2..2....1..3..2
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 30 2013
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