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A283108 Number of fixed polyominoes minus number of free polyominoes for order n. 1
0, 0, 1, 4, 14, 51, 181, 652, 2356, 8625, 31791, 118195, 442261, 1665299, 6302903, 23968090, 91513682, 350687935, 1348198490, 5198114444, 20094107710, 77860452105, 302340714990, 1176325327796, 4584989069865, 17900574971247, 69993587545033, 274071021159757, 1074577571232370 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

a(n) is the number of fixed polyominoes that are a transform - except through identity - of a canonical polyomino.

E.g., n=3:

      A001168

________|_________

|                  |

A000105 | A283108

canon   | transform

        |

*       |

*       |

*       |  * * *

        |

*       |    *   * *   * *

* *     |  * *     *   *

LINKS

Table of n, a(n) for n=0..28.

FORMULA

a(n) = A001168(n) - A000105(n).

CROSSREFS

Cf. A000105, A001168.

Sequence in context: A117421 A034743 A096241 * A211303 A247415 A292463

Adjacent sequences:  A283105 A283106 A283107 * A283109 A283110 A283111

KEYWORD

nonn

AUTHOR

Francois Alcover, Feb 28 2017

STATUS

approved

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Last modified May 26 22:58 EDT 2020. Contains 334634 sequences. (Running on oeis4.)