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A271858 Number of ways to trisect a triangle with side length n exactly into three identical parts in a triangular lattice. 0
0, 1, 1, 2, 5, 20, 56, 276, 2136, 13756, 148352, 2727448, 41044816, 1056334024, 46033137324 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

In the case that n is not divisible by 3 the central triangle is removed, otherwise the dissection would not be possible.

LINKS

Table of n, a(n) for n=1..15.

G. P. Jelliss, Trisected Triangles, The Games and Puzzles Journal, Issue 22, January-April 2002.

CROSSREFS

Cf. A268606, A271857, A113900, A257952.

Sequence in context: A168541 A124264 A274239 * A189734 A221678 A297350

Adjacent sequences: A271855 A271856 A271857 * A271859 A271860 A271861

KEYWORD

nonn,more

AUTHOR

Andrew Howroyd, Apr 15 2016

STATUS

approved

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Last modified February 6 21:39 EST 2023. Contains 360111 sequences. (Running on oeis4.)