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A057712 Number of "polyhes" of order n: a polyhe of order n is obtained by taking a polyhex made of n hexagons (A000228); cutting each of the n hexagons along a diameter and throwing away half that hexagon, in such a way that the remaining figure (made of n half-hexagons) is connected. 1
1, 4, 13, 60, 276, 1416, 7201, 37972 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

REFERENCES

Enumeration attributed by Andrew Clarke to Brendan Owen.

LINKS

Andrew Clarke, Polyhes

Picture from Andrew Clarke's page showing triangle formed by combining polyhes of orders 1, 2 and 3.

Eric Weisstein's World of Mathematics, Polyhe

CROSSREFS

Sequence in context: A149486 A115455 A149487 * A135312 A005035 A052415

Adjacent sequences:  A057709 A057710 A057711 * A057713 A057714 A057715

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Oct 27 2000

EXTENSIONS

Link updated by William Rex Marshall (w.r.marshall(AT)actrix.co.nz), Dec 16 2009

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Last modified February 17 18:20 EST 2012. Contains 206061 sequences.