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A224028 Number of 6Xn 0..3 arrays with rows nondecreasing and antidiagonals unimodal.

%I A224028 #6 Jul 23 2025 04:54:27
%S A224028 4096,1000000,30756756,403836633,3491241557,23151623729,126168072638,
%T A224028 589287463547,2427724545612,9007001464858,30566042176352,
%U A224028 96033091778636,282028543897612,780257746938799,2046679053764299,5117642427934938
%N A224028 Number of 6Xn 0..3 arrays with rows nondecreasing and antidiagonals unimodal.
%C A224028 Row 6 of A224024
%H A224028 R. H. Hardin, <a href="/A224028/b224028.txt">Table of n, a(n) for n = 1..210</a>
%F A224028 Empirical: a(n) = (42587101/1600593426432000)*n^18 + (23341517/16167610368000)*n^17 + (15783371/356638464000)*n^16 + (31606091/33965568000)*n^15 + (17663092277/1207084032000)*n^14 + (133630090943/747242496000)*n^13 + (3090381263819/1810626048000)*n^12 + (861240248921/67060224000)*n^11 + (16435251844841/219469824000)*n^10 + (3455775661663/10450944000)*n^9 + (654929669980007/603542016000)*n^8 + (1738593710779/653184000)*n^7 + (82071435647381/16717428000)*n^6 + (429177771626699/59439744000)*n^5 - (15320544442081/40864824000)*n^4 - (2761354550633/92664000)*n^3 - (36294722496521/593762400)*n^2 + (776634903133/6126120)*n + 95040 for n>4
%e A224028 Some solutions for n=3
%e A224028 ..0..0..2....0..0..0....0..0..2....0..0..0....0..0..0....0..0..0....0..0..2
%e A224028 ..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
%e A224028 ..0..0..0....1..2..3....0..2..3....0..0..3....1..2..3....2..2..2....0..2..2
%e A224028 ..1..1..3....0..1..3....1..1..2....1..1..1....1..3..3....1..1..2....1..1..3
%e A224028 ..0..1..2....0..2..2....1..1..1....1..2..3....1..1..3....1..2..2....0..1..1
%e A224028 ..1..1..2....0..0..1....0..1..1....2..3..3....1..1..3....0..0..1....1..2..2
%K A224028 nonn
%O A224028 1,1
%A A224028 _R. H. Hardin_ Mar 30 2013