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A223997 Number of nX6 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.

%I A223997 #6 Jul 23 2025 04:48:31
%S A223997 28,469,4614,36845,281271,2160036,16795265,131782267,1040869367,
%T A223997 8260503068,65781844983,525128814213,4199218263977,33618978354499,
%U A223997 269371779362318,2159531269883408,17319319103903054,138936031415524052
%N A223997 Number of nX6 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.
%C A223997 Column 6 of A223999
%H A223997 R. H. Hardin, <a href="/A223997/b223997.txt">Table of n, a(n) for n = 1..210</a>
%F A223997 Empirical: a(n) = 28*a(n-1) -300*a(n-2) +1417*a(n-3) -1482*a(n-4) -11436*a(n-5) +31851*a(n-6) +52359*a(n-7) -290782*a(n-8) +153075*a(n-9) +602260*a(n-10) -176604*a(n-11) -1863678*a(n-12) +536713*a(n-13) +8514601*a(n-14) -7251292*a(n-15) -64571700*a(n-16) +163992784*a(n-17) -63488599*a(n-18) +75157211*a(n-19) -574679221*a(n-20) +1117201234*a(n-21) -1103109981*a(n-22) +247796355*a(n-23) -1415805562*a(n-24) +12828520548*a(n-25) -5049431870*a(n-26) +5717879992*a(n-27) +7921013636*a(n-28) +14497424532*a(n-29) -1161322200*a(n-30) +7782865280*a(n-31) +2703305984*a(n-32) +21857003968*a(n-33) +1446146688*a(n-34) +6372675072*a(n-35) -1634756608*a(n-36) +2474711040*a(n-37) -114278400*a(n-38) +967065600*a(n-39) for n>44
%e A223997 Some solutions for n=3
%e A223997 ..0..0..0..1..2..2....0..0..1..1..2..2....0..0..0..0..0..0....0..0..0..1..1..1
%e A223997 ..2..2..2..2..2..2....0..1..1..2..2..2....0..1..1..2..2..2....0..0..0..1..1..2
%e A223997 ..0..2..2..2..2..2....0..1..1..1..2..2....1..2..2..2..2..2....0..0..0..1..1..1
%K A223997 nonn
%O A223997 1,1
%A A223997 _R. H. Hardin_ Mar 30 2013