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Search: id:A047937
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A047937 Number of 2-colorings of an n X n grid, up to rotational symmetry. +0
10
1, 2, 6, 140, 16456, 8390720, 17179934976, 140737496748032, 4611686019501162496, 604462909807864344215552, 316912650057057631849169289216, 664613997892457937028364283517337600 (list; graph; listen)
OFFSET

0,2

FORMULA

a(n) = (m^(n^2) + 2 m^((n^2 + 3 (n mod 2))/4) + m^((n^2 + (n mod 2))/2))/4, with m = 2

EXAMPLE

a(2)=6 from

00 10 11 10 11 11

00 00 00 01 10 11

CROSSREFS

Cf. A054247, A047937-A047945.

Adjacent sequences: A047934 A047935 A047936 this_sequence A047938 A047939 A047940

Sequence in context: A060001 A101753 A090907 this_sequence A027731 A024397 A015173

KEYWORD

nonn,easy,nice

AUTHOR

Robert W. Pratt (Rob.Pratt(AT)sas.com)

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Last modified October 9 14:06 EDT 2008. Contains 144831 sequences.


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