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A056783 Number of diamond polyominoes with n cells. 3
1, 1, 3, 7, 20, 62, 204, 709, 2526, 9212, 33989, 126838, 476597, 1802618, 6850969, 26153537, 100207548, 385225375 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Also the number of polybricks of size n made of Lego.

LINKS

Table of n, a(n) for n=0..17.

Ed Pegg, Jr., Illustrations of polyforms

M. Keller, More information

M. Vicher, Polyforms

Eric Weisstein's World of Mathematics, Polyrhomb [From Eric W. Weisstein, Apr 24 2009]

CROSSREFS

Cf. A057973.

Sequence in context: A132364 A110490 A132868 * A176697 A071688 A232687

Adjacent sequences:  A056780 A056781 A056782 * A056784 A056785 A056786

KEYWORD

nonn,hard,more

AUTHOR

James A. Sellers, Aug 28 2000

EXTENSIONS

More terms from Don Reble (djr(AT)nk.ca), Nov 01 2001

a(15)-a(18) from Joseph Myers, Nov 15 2010

STATUS

approved

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Last modified May 27 22:57 EDT 2017. Contains 287210 sequences.