A278804 - OEIS

%I #6 Sep 03 2022 21:09:27

%S 21,336,5767,110455,2179956,41299256,725674326,11698232451,

%T 172994405326,2356249442222,29713542257399,348752692539813,

%U 3828597575581476,39486426123589674,384123325152744838,3537191225894230125

%N Number of n X 5 0..2 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order.

%C Column 5 of A278807.

%H R. H. Hardin, <a href="/A278804/b278804.txt">Table of n, a(n) for n = 1..109</a>

%e Some solutions for n=4

%e ..1..1..1..1..0. .1..1..0..0..0. .1..1..0..0..0. .1..1..0..0..0

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

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

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

%Y Cf. A278807.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 28 2016