A047939 Number of 4-colorings of an n X n grid, up to rotational symmetry.

1, 4, 70, 65824, 1073758336, 281474993496064, 1180591620734591303680, 79228162514264619068554215424, 85070591730234615870455337878516924416, 1461501637330902918203686041642102636484130504704, 401734511064747568885490523085607563280607806359022338048000

Offset

0,2

Links

Andrew Howroyd, Table of n, a(n) for n = 0..25

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 = 4.

Crossrefs

Column k=4 of A343095.

Cf. A054751, A047937.

Sequence in context: A184576 A367523 A162135 * A354859 A088693 A322397

Adjacent sequences: A047936 A047937 A047938 * A047940 A047941 A047942

Keyword

nonn

Author

Rob Pratt

Extensions

Terms a(10) and beyond from Andrew Howroyd, Apr 14 2021

Status

approved