A123803 - OEIS

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A123803

Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1x7 which is symmetric after a rotation by 180 degrees.

1, 2, 52, 617, 6052, 86534, 814679, 12560687 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	REFERENCES	`M. Abrahamsen and S. Eilers, Efficient counting of LEGO buildings, in preparation` `B. Durhuus and S. Eilers, On the entropy of LEGO, arXiv:math.CO/0504039`
	LINKS	`S. Eilers, LEGO counts`
	CROSSREFS	`Sequence in context: A080921 A034311 A053317 * A101930 A174779 A099882` `Adjacent sequences: A123800 A123801 A123802 * A123804 A123805 A123806`
	KEYWORD	`nonn`
	AUTHOR	`Soren Eilers (eilers(AT)math.ku.dk), Oct 29 2006`

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Last modified February 16 20:28 EST 2012. Contains 205962 sequences.