A047942 Number of 7-colorings of an n X n grid, up to rotational symmetry.

1, 7, 616, 10092775, 8308234084801, 335267154940213889575, 662932711464913775048175499816, 64230894380264719522488136461023341060807, 304940121908958925034643465916849873749900601574419201, 70938377295002676956115265690779190293441720530070400876280330568007

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 = 7.

Crossrefs

Column k=7 of A343095.

Cf. A047937.

Sequence in context: A261532 A295814 A087772 * A319033 A182346 A333741

Adjacent sequences: A047939 A047940 A047941 * A047943 A047944 A047945

Keyword

nonn

Author

Rob Pratt

Extensions

Terms a(8) and beyond from Andrew Howroyd, Apr 14 2021

Status

approved