%I #5 Mar 31 2012 12:37:03
%S 318,1616,7070,34100,157872,752028,3530808,16789864,79293448,
%T 377319812,1788274836,8518844116,40475837046,193014313760,
%U 918808191844,4385300981366,20905548073454,99850385810890,476532537931898
%N Number of (n+1)X4 0..2 arrays with the permanents of all 2X2 subblocks equal and nonzero
%C Column 3 of A204840
%H R. H. Hardin, <a href="/A204835/b204835.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 8*a(n-1) +46*a(n-2) -463*a(n-3) -827*a(n-4) +11584*a(n-5) +7209*a(n-6) -167177*a(n-7) -24235*a(n-8) +1555772*a(n-9) -108939*a(n-10) -9844492*a(n-11) +1639028*a(n-12) +43404736*a(n-13) -9040868*a(n-14) -134200436*a(n-15) +30728164*a(n-16) +288648563*a(n-17) -71549296*a(n-18) -422266864*a(n-19) +116364363*a(n-20) +403049929*a(n-21) -126818335*a(n-22) -233198888*a(n-23) +83721106*a(n-24) +71218296*a(n-25) -28108413*a(n-26) -8643432*a(n-27) +3559710*a(n-28) +142560*a(n-29) -78408*a(n-30)
%e Some solutions for n=4
%e ..1..1..1..2....1..0..1..2....2..2..1..2....2..1..0..1....0..1..1..0
%e ..0..2..0..2....2..1..0..1....1..2..2..2....0..1..2..2....1..0..1..1
%e ..1..1..1..1....1..0..1..2....2..2..1..2....2..1..0..1....1..1..0..1
%e ..1..1..1..1....0..1..0..1....1..2..2..2....2..0..2..2....0..1..1..2
%e ..0..2..0..2....1..1..1..0....2..2..1..2....2..1..1..0....1..1..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Jan 19 2012