A215295 - OEIS

%I #4 Aug 07 2012 11:50:17

%S 1,10,70,2100,23100,1051050,14294280,814773960,12547518984,

%T 824551247520,13781785137120,999179422441200,17699749768958400,

%U 1379105502831342000,25513451802379827000,2100607531729272423000,40191624107086745693400

%N Number of permutations of 0..floor((n*5-2)/2) on odd squares of an nX5 array such that each row and column of odd squares is increasing

%C Column 5 of A215297

%H R. H. Hardin, <a href="/A215295/b215295.txt">Table of n, a(n) for n = 1..210</a>

%F f3=floor((n+1)/2)

%F f4=floor(n/2)

%F a(n) = A060854(2,f3)*A060854(3,f4)*binomial(2*f3+3*f4,2*f3)

%e Some solutions for n=5

%e ..x..2..x..6..x....x..1..x..5..x....x..0..x..5..x....x..0..x..2..x

%e ..0..x..3..x..4....0..x..2..x..7....2..x..4..x.10....3..x..6..x..8

%e ..x..5..x.10..x....x..3..x..9..x....x..1..x..8..x....x..1..x..7..x

%e ..1..x..7..x..8....4..x..6..x.11....6..x..7..x.11....4..x..9..x.11

%e ..x..9..x.11..x....x..8..x.10..x....x..3..x..9..x....x..5..x.10..x

%K nonn

%O 1,2

%A _R. H. Hardin_ Aug 07 2012