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A290653 Number of perfect dissections of equilateral triangles into n equilateral triangles with integer sides. 4
2, 2, 6, 23, 64, 181 (list; graph; refs; listen; history; text; internal format)
OFFSET
15,1
COMMENTS
A perfect dissection has no two triangles of the same side. Triangles of different orientation are counted separately. The computation by A. Drapal and C. Hamalainen proves Tutte's conjecture that the smallest perfect dissection has size 15.
LINKS
Ales Drapal and Carlo Hamalainen, An enumeration of equilateral triangle dissections, arXiv:0910.5199 [math.CO], 2009-2010.
W. T. Tutte, The dissection of equilateral triangles into equilateral triangles. Mathematical Proceedings of the Cambridge Philosophical Society, 44(4), 463-482. doi:10.1017/S030500410002449X
CROSSREFS
Sequence in context: A112478 A184715 A292319 * A138801 A188958 A141902
KEYWORD
nonn,more,hard
AUTHOR
Hugo Pfoertner, Aug 08 2017
STATUS
approved

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Last modified April 12 22:48 EDT 2024. Contains 371639 sequences. (Running on oeis4.)