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%I #4 Sep 24 2012 09:03:16
%S 16,70225,103754596,174892912804,287247245656900,473216230511351044,
%T 778956312256094880625,1282337355733724881761856,
%U 2110951958198074542626828769,3475005538598697157658237172049
%N Number of city-block distance 1, pressure limit 2 movements in an nX6 array with each element moving exactly one horizontally or vertically and no element acquiring more than two neighbors
%C Column 6 of A217028
%H R. H. Hardin, <a href="/A217026/b217026.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=2 (movement: 0=n 1=e 2=s 3=w)
%e ..2..3..2..3..1..3....1..2..2..3..3..3....2..2..1..3..3..2....2..3..2..2..2..3
%e ..0..1..1..1..1..0....0..0..3..3..0..3....0..3..0..1..1..3....0..0..0..1..0..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Sep 24 2012