A140650 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.

0, 3, 48, 600, 32256, 1177344, 268369920, 36506664960, 35184338534400, 18577347909255168, 73786976226118729728, 153476910691030086451200, 2475880078570197599844827136, 20440865928680162788862343512064, 1329227995784915854457062986570792960

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Formula

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

a(2n+1) = 2^(2n^2+3n+1)-2^(n^2+2n+1). (corrected by Colin Barker, Mar 28 2014)

Prog

(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

Crossrefs

Cf. A054257, A054407.

Sequence in context: A354132 A335178 A260347 * A081540 A294829 A264730

Adjacent sequences: A140647 A140648 A140649 * A140651 A140652 A140653

Keyword

nonn

Author

Anthony C Robin, Jul 09 2008

Extensions

More terms from Colin Barker, Mar 28 2014

Status

approved