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A231421 Number of (2+1)X(n+1) 0..2 arrays with no element equal to a strict majority of its horizontal, diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order.

%I A231421 #6 Jul 23 2025 06:28:55
%S A231421 50,1032,20896,424404,8704406,178277756,3654045516,74894704740,
%T A231421 1535161355750,31467342399888,645012980337444,13221399981059518,
%U A231421 271010854744794084,5555152819316036170,113868962991822419034
%N A231421 Number of (2+1)X(n+1) 0..2 arrays with no element equal to a strict majority of its horizontal, diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order.
%C A231421 Row 2 of A231419
%H A231421 R. H. Hardin, <a href="/A231421/b231421.txt">Table of n, a(n) for n = 1..210</a>
%F A231421 Empirical: a(n) = 20*a(n-1) +56*a(n-2) -821*a(n-3) -2559*a(n-4) +2274*a(n-5) +11333*a(n-6) +75045*a(n-7) +58970*a(n-8) -744820*a(n-9) -338743*a(n-10) +3350990*a(n-11) -566226*a(n-12) -8533262*a(n-13) +6626396*a(n-14) +10836980*a(n-15) -13238580*a(n-16) -6337152*a(n-17) +13746128*a(n-18) -1255112*a(n-19) -8079152*a(n-20) +2081168*a(n-21) +460736*a(n-22) -1034208*a(n-23) +221216*a(n-24) -114304*a(n-25) -122880*a(n-26) -16384*a(n-27) -512*a(n-28)
%e A231421 Some solutions for n=3
%e A231421 ..0..1..2..1....0..1..0..1....0..1..1..2....0..1..2..1....0..1..0..2
%e A231421 ..1..0..0..1....1..0..2..0....1..2..2..0....1..0..2..1....0..0..2..0
%e A231421 ..1..2..1..1....0..2..2..0....0..2..2..1....1..0..2..0....1..2..2..0
%K A231421 nonn
%O A231421 1,1
%A A231421 _R. H. Hardin_, Nov 08 2013