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A075221 Number of polyiamonds with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion). 10
1, 1, 1, 3, 4, 12, 21, 56, 111, 262, 462, 1453, 1875, 4734, 9410, 20603, 24034, 79352, 79925, 273731, 358096, 669640, 796571, 3342349, 2980476, 6387513, 10167660, 24999509, 21477012, 87978317 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

REFERENCES

Branko Gr├╝nbaum 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, A075220, A075222, A075223, A075224, A075203, A075212.

Sequence in context: A292551 A227429 A075220 * A295948 A129922 A005221

Adjacent sequences:  A075218 A075219 A075220 * A075222 A075223 A075224

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

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Last modified November 17 00:08 EST 2019. Contains 329209 sequences. (Running on oeis4.)