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A208257 Number of nX7 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.

%I A208257 #7 Jul 22 2025 21:15:22
%S A208257 365,393216,415737216,439026252912,463586569433280,489518751475118880,
%T A208257 516901401841519506624,545815772261840889783840,
%U A208257 576347550907375513255891248,608587212579607572737693478288
%N A208257 Number of nX7 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.
%C A208257 Column 7 of A208258
%H A208257 R. H. Hardin, <a href="/A208257/b208257.txt">Table of n, a(n) for n = 1..210</a>
%F A208257 Empirical: a(n) = 1373*a(n-1) -382385*a(n-2) +54747930*a(n-3) -5050986386*a(n-4) +332267679041*a(n-5) -16472142082703*a(n-6) +636007583672478*a(n-7) -19508251954601454*a(n-8) +480569383283952657*a(n-9) -9546208348531626993*a(n-10) +152598952268814061851*a(n-11) -1946846244225175080346*a(n-12) +19518911243309328077698*a(n-13) -150002896733353526035184*a(n-14) +849776274453519925228352*a(n-15) -3327166677806732426576264*a(n-16) +7899544532604413646690344*a(n-17) -6508673827964553701633600*a(n-18) -20940104457639861466791296*a(n-19) +72463799516214011378881024*a(n-20) -61429017906552923870936064*a(n-21) -129536619155578798140518400*a(n-22) +380737956559758296779800576*a(n-23) -211491273596407625450717184*a(n-24) -649598231455057371522924544*a(n-25) +1411628961483792374550233088*a(n-26) -535856510128456063711707136*a(n-27) -2479363142583076923579039744*a(n-28) +5970652384046936507902066688*a(n-29) -7499573050858256420655071232*a(n-30) +6280307951272279750928760832*a(n-31) -3675985493399257320121171968*a(n-32) +1481320042982141475269115904*a(n-33) -383743024338594997911683072*a(n-34) +54171200367877184095780864*a(n-35) -2546711369956156422225920*a(n-36) for n>37
%e A208257 Some solutions for n=4
%e A208257 ..0..1..2..1..1..1..0....0..1..0..2..1..2..2....0..0..0..0..1..1..1
%e A208257 ..1..2..0..1..2..2..1....1..2..0..1..2..0..0....2..0..1..2..0..2..1
%e A208257 ..0..0..1..2..1..0..2....2..0..1..2..0..1..0....1..1..2..0..1..0..0
%e A208257 ..1..2..2..0..0..2..1....1..2..0..1..2..2..0....0..2..1..2..1..2..0
%K A208257 nonn
%O A208257 1,1
%A A208257 _R. H. Hardin_ Feb 24 2012