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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A206856 Number of n X n 0..2 arrays avoiding the pattern z z+1 z in any row, column, diagonal or antidiagonal.

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%I A206856 #8 Jul 22 2025 19:43:42
%S A206856 3,81,11092,7598355,31208037240,729358354663001,92792498733436652359
%N A206856 Number of n X n 0..2 arrays avoiding the pattern z z+1 z in any row, column, diagonal or antidiagonal.
%C A206856 Diagonal of A206863
%e A206856 Some solutions for n=4
%e A206856 ..0..2..2..2....2..0..1..2....0..2..2..0....0..2..0..1....2..2..2..1
%e A206856 ..1..1..0..2....0..2..2..0....1..0..0..0....2..0..1..1....2..1..0..2
%e A206856 ..2..0..1..1....2..2..0..1....2..2..1..2....0..2..1..1....2..0..0..2
%e A206856 ..2..2..1..2....2..1..2..2....0..1..2..2....2..0..0..1....1..0..1..2
%K A206856 nonn
%O A206856 1,1
%A A206856 _R. H. Hardin_ Feb 13 2012

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