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A198714 Number of nX7 0..3 arrays with values 0..3 introduced in row major order and no element equal to any horizontal or vertical neighbor.

%I A198714 #7 Jul 22 2025 13:05:40
%S A198714 122,58825,28609241,13925032958,6778819400772,3300094936852775,
%T A198714 1606578861528554441,782129027546108478208,380763168247444298026697,
%U A198714 185366606445710896112671190,90241867886483759053800200221
%N A198714 Number of nX7 0..3 arrays with values 0..3 introduced in row major order and no element equal to any horizontal or vertical neighbor.
%C A198714 Column 7 of A198715
%H A198714 R. H. Hardin, <a href="/A198714/b198714.txt">Table of n, a(n) for n = 1..126</a>
%F A198714 Empirical: a(n) = 820*a(n-1) -205689*a(n-2) +23977335*a(n-3) -1448890080*a(n-4) +40681354716*a(n-5) +113470351405*a(n-6) -45083135350759*a(n-7) +1384281526165416*a(n-8) -16268081626571563*a(n-9) -63890727017432669*a(n-10) +4141584863538946248*a(n-11) -41819886892303325457*a(n-12) -30483804619910407683*a(n-13) +3863177257558021068078*a(n-14) -27574675558592643871665*a(n-15) -5974253069771812381395*a(n-16) +994204560645628682891988*a(n-17) -4133294712546191129276631*a(n-18) -5200219344858789634094007*a(n-19) +79782056692975632581941806*a(n-20) -145976694071885459756226729*a(n-21) -381423099164490179830401489*a(n-22) +1687752294947845021038392100*a(n-23) -947863788801858331624770840*a(n-24) -4416578720165084280803867511*a(n-25) +7519754083669273956859949007*a(n-26) -393515001351016977961508328*a(n-27) -8318760918675594342013626309*a(n-28) +7729370069736269915861360652*a(n-29) -2679235928159828068047490236*a(n-30) +224133015493782945421410924*a(n-31) +60130490872795258151715444*a(n-32) -9198797534128825159826898*a(n-33)
%e A198714 Some solutions with all values from 0 to 3 for n=4
%e A198714 ..0..1..0..2..0..1..2....0..1..0..2..0..3..0....0..1..0..2..1..3..1
%e A198714 ..1..0..2..0..2..3..1....1..0..2..0..2..1..3....1..0..2..0..3..1..0
%e A198714 ..0..1..0..2..1..2..0....0..1..0..2..0..3..1....0..1..0..2..1..0..3
%e A198714 ..1..0..2..0..3..1..2....1..0..2..0..3..0..3....1..0..2..0..2..3..1
%K A198714 nonn
%O A198714 1,1
%A A198714 _R. H. Hardin_ Oct 29 2011