OFFSET
1,2
LINKS
Peter Kagey, Illustration of a(3)=136
Peter Kagey and William Keehn, Counting tilings of the n X m grid, cylinder, and torus, arXiv: 2311.13072 [math.CO], 2023. See also J. Int. Seq., (2024) Vol. 27, Art. No. 24.6.1, pp. A-6, A-10.
FORMULA
a(2*n-1) = 2^(2n^2 - 4n - 1)*(4^n + 4^n^2).
a(2*n) = 2^(n^2 - 2)*(2 + 2^n^2 + 8^n^2).
MATHEMATICA
Table[{2^(2 m^2 - 4 m - 1)*(4^m + 4^m^2), 2^(m^2 - 2)*(2 + 2^m^2 + 8^m^2)}, {m, 1, 5}] // Flatten
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Kagey, Dec 11 2023
STATUS
approved