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A223996 Number of nX5 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.

%I A223996 #6 Jul 23 2025 04:48:15
%S A223996 21,281,2403,17929,132119,984595,7400832,55978489,425257387,
%T A223996 3240026429,24732295031,189012200658,1445524081573,11059812977060,
%U A223996 84641528773971,647871404690124,4959498660501284,37967742496830194,290676685330836460
%N A223996 Number of nX5 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.
%C A223996 Column 5 of A223999
%H A223996 R. H. Hardin, <a href="/A223996/b223996.txt">Table of n, a(n) for n = 1..210</a>
%F A223996 Empirical: a(n) = 21*a(n-1) -155*a(n-2) +405*a(n-3) +365*a(n-4) -2996*a(n-5) -664*a(n-6) +18276*a(n-7) -22433*a(n-8) -2304*a(n-9) -9369*a(n-10) -7644*a(n-11) +222262*a(n-12) +167540*a(n-13) -1508772*a(n-14) +2046821*a(n-15) -1097976*a(n-16) +4265706*a(n-17) -2582500*a(n-18) -941886*a(n-19) -2423080*a(n-20) +19902336*a(n-21) +2548764*a(n-22) +9439760*a(n-23) +1688032*a(n-24) +1035840*a(n-25) -957120*a(n-26) +1996416*a(n-27) -115200*a(n-28) for n>31
%e A223996 Some solutions for n=3
%e A223996 ..0..0..0..0..0....0..1..1..1..1....0..0..0..0..0....1..1..1..1..2
%e A223996 ..0..0..0..2..2....1..1..1..1..1....0..1..1..1..2....0..2..2..2..2
%e A223996 ..1..1..1..1..2....0..1..1..2..2....0..2..2..2..2....2..2..2..2..2
%K A223996 nonn
%O A223996 1,1
%A A223996 _R. H. Hardin_ Mar 30 2013