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%I #5 Mar 31 2012 12:36:40
%S 15,2614,583813,132636590,30147154218,6852264918471,1557479347400065,
%T 354005859128023982,80463441477635545163,18288865135614195620421,
%U 4156951055108642793860100,944850429287655687332694651
%N Number of nX4 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors
%C Column 4 of A200801
%H R. H. Hardin, <a href="/A200797/b200797.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 226*a(n-1) +397*a(n-2) -21234*a(n-3) -497498*a(n-4) +2087766*a(n-5) +34773209*a(n-6) -15109862*a(n-7) -1344245435*a(n-8) +6305961810*a(n-9) -9646383486*a(n-10) -311210406120*a(n-11) +818951464312*a(n-12) +7068765097660*a(n-13) -15075608645540*a(n-14) -89765346075158*a(n-15) +83122511102408*a(n-16) +562758507641100*a(n-17) +211301619877576*a(n-18) -1363882902513610*a(n-19) -3093844768642228*a(n-20) +3909385497592574*a(n-21) +12063883361116060*a(n-22) -8119400268962692*a(n-23) -27724078036879543*a(n-24) -2195647624835104*a(n-25) +17503376946283795*a(n-26) +13937597848821644*a(n-27) +21063587960493070*a(n-28) +19559907770565622*a(n-29) -10692765489736685*a(n-30) -24922540031602668*a(n-31) -4863390875436761*a(n-32) -21563816326872032*a(n-33) -31429218919732322*a(n-34) -6405644638575092*a(n-35) +28158640181918660*a(n-36) +26831253270589974*a(n-37) +12473963843739616*a(n-38) +1775794465292012*a(n-39) -5284490896805036*a(n-40) -6920386914042164*a(n-41) -4547920088065892*a(n-42) -1201731389529908*a(n-43) +263989556748732*a(n-44) +650291914832328*a(n-45) +365189349172464*a(n-46) +98577715906512*a(n-47) -3548230253856*a(n-48) -15222363587136*a(n-49) -7040558081664*a(n-50) -2182723137792*a(n-51) -417125915136*a(n-52) -58773123072*a(n-53) for n>54
%e Some solutions for n=3
%e ..0..1..2..0....0..1..1..0....0..1..1..2....0..0..1..1....0..1..0..2
%e ..0..1..2..1....0..1..0..0....0..1..1..0....0..1..1..0....1..0..1..3
%e ..3..0..3..0....1..2..2..2....0..3..3..1....2..1..2..3....1..1..1..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Nov 22 2011