A075220 Number of polyiamonds with n cells that tile the plane by 180-degree rotation (Conway criterion).

1, 1, 1, 3, 4, 12, 21, 56, 111, 261, 462, 1431, 1875, 4696, 9410, 20099, 24034, 77884, 79925, 266786, 358096, 658594, 796571, 3227163, 2980476, 6268017, 10167660, 24321735, 21477012, 85964698

Offset

1,4

References

Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4.

Links

Table of n, a(n) for n=1..30.

Joseph Myers, Polyiamond tiling

Crossrefs

Cf. A071332, A075216, A075217, A075218, A075219, A075221, A075222, A075223, A075224, A075202, A075211.

Sequence in context: A101727 A292551 A227429 * A075221 A295948 A129922

Adjacent sequences: A075217 A075218 A075219 * A075221 A075222 A075223

Keyword

hard,nonn

Author

Joseph Myers, Sep 08 2002

Extensions

More terms from Joseph Myers, Nov 11 2003

a(29) and a(30) from Joseph Myers, Nov 21 2010

Status

approved