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A202976 Number of nX5 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

%I A202976 #7 Jul 22 2025 16:54:55
%S A202976 1,14,215,2582,31380,379788,4590696,55723864,676981428,8220515870,
%T A202976 99804610105,1211737645986,14712070032443,178624535138225,
%U A202976 2168744883228649,26331490124843751,319699729136522144
%N A202976 Number of nX5 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.
%C A202976 Column 5 of A202979
%H A202976 R. H. Hardin, <a href="/A202976/b202976.txt">Table of n, a(n) for n = 1..210</a>
%F A202976 Empirical: a(n) = 21*a(n-1) -168*a(n-2) +988*a(n-3) -4019*a(n-4) +14018*a(n-5) -38338*a(n-6) +76250*a(n-7) -75318*a(n-8) -25048*a(n-9) -2704*a(n-10) +284955*a(n-11) -215394*a(n-12) -880505*a(n-13) -242350*a(n-14) +5521214*a(n-15) +653795*a(n-16) -10478457*a(n-17) -9279936*a(n-18) +15930956*a(n-19) +21911876*a(n-20) -8411513*a(n-21) -37124626*a(n-22) -3849041*a(n-23) +23286499*a(n-24) -8400505*a(n-25) -9905859*a(n-26) +47524429*a(n-27) +20129245*a(n-28) -116149038*a(n-29) +2411219*a(n-30) +172063757*a(n-31) -3388918*a(n-32) -136545864*a(n-33) -28219012*a(n-34) +67852922*a(n-35) +54667307*a(n-36) +2102952*a(n-37) -12764701*a(n-38) -5492419*a(n-39) -787424*a(n-40) +318583*a(n-41) +347059*a(n-42) +193761*a(n-43) +39772*a(n-44) -696*a(n-45) -1216*a(n-46)
%e A202976 Some solutions for n=5
%e A202976 ..1..1..1..1..1....0..1..1..0..0....1..1..1..1..0....1..1..0..0..0
%e A202976 ..1..0..1..1..1....0..1..1..1..1....1..1..0..1..1....1..1..0..1..1
%e A202976 ..1..0..0..1..1....0..1..1..0..1....1..1..0..0..1....1..1..0..1..1
%e A202976 ..1..1..1..1..0....0..1..0..1..1....0..0..1..1..1....1..0..1..1..1
%e A202976 ..1..1..1..1..0....0..1..1..1..1....0..0..1..1..1....1..1..1..0..0
%K A202976 nonn
%O A202976 1,2
%A A202976 _R. H. Hardin_ Dec 26 2011