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A162677 Number of different fixed (possibly) disconnected polyominoes (of any area) bounded (not necessarily tightly) by an n*n square 5
1, 10, 400, 57856, 31522816, 66605547520, 554222579875840, 18303191835587117056, 2408425353007592768536576, 1265177138001297870205254369280, 2655861110791164560222750369099284480 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

FORMULA

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

EXAMPLE

a(2)=10: the monomino, 4 dominoes (2 strictly disconnected), 4 rotations of the L tromino, and the square tetromino

CROSSREFS

Cf. A162673, A162674, A162675, A162676

Sequence in context: A183487 A172505 A098722 * A041767 A130557 A085000

Adjacent sequences:  A162674 A162675 A162676 * A162678 A162679 A162680

KEYWORD

nonn

AUTHOR

David Bevan (dbevan(AT)emtex.com), Jul 27 2009

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Last modified February 14 17:10 EST 2012. Contains 205644 sequences.