A390996 Number of free polyaboloes (or polytans) with n cells, where two triangles sharing a hypotenuse (making up a square) are counted as a single cell.

2, 4, 16, 75, 409, 2491, 15814, 103727, 692428, 4689112

Offset

1,1

Links

Table of n, a(n) for n=1..10.

Pontus von Brömssen, Illustration for n<=3.

Pontus von Brömssen, Illustration for n=4.

Crossrefs

Cf. A006074, A390993, A390997 (one-sided), A390998 (fixed), A390999.

Sequence in context: A155519 A180391 A371389 * A275555 A370485 A058926

Adjacent sequences: A390993 A390994 A390995 * A390997 A390998 A390999

Keyword

nonn,more

Author

Pontus von Brömssen, Nov 27 2025

Status

approved