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Number of nX6 0..3 arrays with rows and columns lexicographically nondecreasing read forwards and nonincreasing read backwards
1

%I #5 Mar 31 2012 12:36:46

%S 4,304,117744,91893727,48452117136,13486744809160,2238761872232964,

%T 248685266018356303,19939344176339744246,1214420344528171330419,

%U 58291620982242700295226,2267753515670520458933950

%N Number of nX6 0..3 arrays with rows and columns lexicographically nondecreasing read forwards and nonincreasing read backwards

%C Column 6 of A201981

%H R. H. Hardin, <a href="/A201979/b201979.txt">Table of n, a(n) for n = 1..25</a>

%e Some solutions for n=2

%e ..3..3..3..3..3..3....0..1..2..2..2..2....0..0..1..1..1..1....1..1..3..3..3..3

%e ..3..3..3..3..3..3....3..2..0..0..0..0....3..3..0..0..0..0....3..3..0..0..0..0

%K nonn

%O 1,1

%A _R. H. Hardin_ Dec 07 2011