OFFSET
1,2
LINKS
Peter Kagey, Illustration of a(2)=5
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-9.
FORMULA
a(2m-1) = 2^(2m^2 - 4m - 1)*(4^m + 4^m^2).
a(2m) = (4^m^2 + 16^m^2)/4.
MATHEMATICA
Table[{2^(2 m^2 - 4 m - 1) (4^m + 4^m^2), (4^m^2 + 16^m^2)/4}, {m, 1, 5}] // Flatten
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Kagey, Dec 10 2023
STATUS
approved