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Number of different ways of coloring an n X n grid of squares using two colors so that the resulting grid has just one line of symmetry.
1

%I #9 Mar 29 2014 03:06:32

%S 0,3,48,600,32256,1177344,268369920,36506664960,35184338534400,

%T 18577347909255168,73786976226118729728,153476910691030086451200,

%U 2475880078570197599844827136,20440865928680162788862343512064,1329227995784915854457062986570792960

%N Number of different ways of coloring an n X n grid of squares using two colors so that the resulting grid has just one line of symmetry.

%F a(2n) = 2^(2n^2-1)*(2^n+1)-2^(n^2-1)*(2^n+1).

%F a(2n+1) = 2^(2n^2+3n+1)-2^(n^2+2n+1). (corrected by _Colin Barker_, Mar 28 2014)

%o (PARI) s=[0]; for(n=1, 10, s=concat(s, [2^(2*n^2-1)*(2^n+1)-2^(n^2-1)*(2^n+1), 2^(2*n^2+3*n+1)-2^(n^2+2*n+1)])); s \\ _Colin Barker_, Mar 28 2014

%Y Cf. A054257, A054407.

%K nonn

%O 1,2

%A _Anthony C Robin_, Jul 09 2008

%E More terms from _Colin Barker_, Mar 28 2014