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A056844 Number of polydiamonds: polyominoes made from n diamonds. 2
1, 2, 9, 40, 238, 1517 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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 traditional 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 for A056844 and A056845, but it looks like a possible explanation.

LINKS

Table of n, a(n) for n=1..6.

M. Vicher, Polyforms

M. Vicher, The 40 4-celled polydiamonds

M. Vicher, The 40 4-celled polydiamonds

CROSSREFS

Cf. A056845.

Sequence in context: A261047 A052846 A293152 * A220471 A213095 A238372

Adjacent sequences:  A056841 A056842 A056843 * A056845 A056846 A056847

KEYWORD

nice,nonn,more

AUTHOR

James A. Sellers, Aug 28 2000

EXTENSIONS

Edited by N. J. A. Sloane, Jun 21, 2001

STATUS

approved

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Last modified October 19 05:08 EDT 2018. Contains 316336 sequences. (Running on oeis4.)