A393727 Number of free polyominoes in the {5,7} tessellation of the hyperbolic plane.

1, 1, 2, 8, 33, 194, 1196, 8186, 58001, 426280, 3204913, 24585306, 191642332

Offset

1,3

Links

Table of n, a(n) for n=1..13.

Formula

a(n) = P{p,q}(n) (the number of {p,q} polyominoes of size n) is equal to P{p,oo}(n) for n <= q; also P{p,q}(q+1) = P{p,oo}(q+1) + floor((p-1)/2) - floor((3+q(p-2))/2). In this case, p=5, q=7 and P{p,oo} = A005040.

Crossrefs

Cf. A330211, A393725, A393726, A393728, A005040.

Sequence in context: A393725 A269890 A393726 * A393728 A005040 A380620

Adjacent sequences: A393724 A393725 A393726 * A393728 A393729 A393730

Keyword

nonn,more

Author

John Mason, Érika Roldán, and Rosemberg Toalá-Enríquez, Feb 26 2026

Status

approved