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A126026 Conjectured upper bound on area of the convex hull of any edge-to-edge connected system of regular unit hexagons (n-polyhexes). +0
1
0, 1, 2, 4, 5, 8, 10, 13, 17, 20, 24, 28, 33, 38, 43, 49, 55, 61, 68, 75, 82, 90, 97, 106, 114, 123, 133, 142, 152, 162, 173 (list; graph; listen)
OFFSET

1,3

COMMENT

Kurz proved the polyomino equivalent of this conjecture as A122133 and abstracts: "In this article we prove a conjecture of Bezdek, Brass and Harborth concerning the maximum volume of the convex hull of any facet-to-facet connected system of n unit hypercubes in the d-dimensional Euclidean space. For d=2 we enumerate the extremal polyominoes and determine the set of possible areas of the convex hull for each n."

LINKS

Sascha Kurz, Convex hulls of polyominoes, 26 Feb 2007, Conjecture 2, p. 12.

Eric Weisstein's World of Mathematics, Polyhex.

FORMULA

a(n) = Floor((n^2 + 14*n/3 + 1)/6).

EXAMPLE

a(10) = 24 because floor((10^2 + 14*10/3 + 1)/6) = floor(24.6111111) = 24.

CROSSREFS

Cf. A000228, A036359, A002216, A005963, A000228, A001998, A018190, A001207, A057973, A122133.

Sequence in context: A115793 A076614 A000549 this_sequence A057129 A036404 A018498

Adjacent sequences: A126023 A126024 A126025 this_sequence A126027 A126028 A126029

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post (jvospost3(AT)gmail.com), Feb 27 2007

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Last modified March 19 01:26 EDT 2010. Contains 173632 sequences.


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