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Search: id:A056845
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| A056845 |
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Number of polydiamonds: polyominoes made from n diamonds (another version). |
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+0
2
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OFFSET
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1,2
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COMMENT
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The difference between this and A056844 is not clear to me. Maybe the definition of equivalence has been changed, or the rules concerning planarity or the existence of holes have changed.
Comment from Larry_Reeves(AT)intranetsolutions.com, Jun 22 2001: If you look at Vicher's picture of the 40 4-celled polydiamonds (link in A056844), near the middle of the picture is a polydiamond that looks like the tradiitional 2-D representation of a cube with an extra diamond stuck to the edge. Depending on how you orient the cube, there are actually 2 different ways to form this polydiamond, although there is no change in the perimeter shape. I haven't confirmed that this explains the difference in values for sizes 5 and above, but it looks like a possible explanation.
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LINKS
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M. Keller, More information
M. Vicher, Polyforms
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CROSSREFS
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Cf. A056844.
Sequence in context: A128752 A074611 A020038 this_sequence A092239 A132847 A121365
Adjacent sequences: A056842 A056843 A056844 this_sequence A056846 A056847 A056848
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KEYWORD
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obsc,nonn,more
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AUTHOR
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James A. Sellers (sellersj(AT)math.psu.edu), Aug 28 2000
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