A068294 1/5 the number of colorings of an n X n octagonal array with 5 colors.

1, 24, 1344, 187008, 65012352, 56638464768, 123968096842368, 682463815024774272, 9455897825697924931968, 329835949030491781985964672, 28967729014957963606903092579840, 6405563550899359667890368716213003520, 3566277295414164369700428069692324488565760, 4998812913455162820842387241261713638306330756608

Offset: 1

Author

R. H. Hardin, Feb 24 2002

Keywords

• nonn

Links

• Christian Gaetz and Yibo Gao, Interlacing triangles, Schubert puzzles, and graph colorings, arXiv:2408.07863 [math.CO], 2024. See p. 15. See also Sém. Lothar. Combin., (2025) Vol. 93B, Art. No. 26. See p. 10.

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A212208, A212209.

Extensions

a(8) from Alois P. Heinz, May 03 2012

a(9)-a(14) from Andrew Howroyd, Jun 25 2017