

A003448


Number of nonequivalent dissections of an ngon into n4 polygons by nonintersecting diagonals rooted at a cell up to rotation and reflection.
(Formerly M2993)


3



1, 3, 15, 81, 422, 2124, 10223, 47813, 218130, 977354, 4315130, 18833538, 81424236, 349303352, 1488748719, 6310303727, 26621551418, 111854042306, 468309841090, 1954642186302, 8136002036672, 33782928166668, 139971138117190, 578803145957026
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OFFSET

5,2


COMMENTS

Number of dissections of regular ngon into n4 polygons with reflection and rooted at a cell. Sean A. Irvine, May 13 2015
The dissection will always be composed of either 1 pentagon and n5 triangles or 2 quadrilaterals and n6 triangles.  Andrew Howroyd, Nov 24 2017


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Andrew Howroyd, Table of n, a(n) for n = 5..200
P. Lisonek, Closed forms for the number of polygon dissections, Journal of Symbolic Computation 20 (1995), 595601.
C. R. Read, On general dissections of a polygon, Aequat. math. 18 (1978) 370388.


PROG

(PARI) \\ See A003447 for DissectionsModDihedralRooted()
my(v=DissectionsModDihedralRooted(apply(i>if(i>=3&&i<=5, y^(i3)+O(y^3)), [1..30]))); apply(p>polcoeff(p, 2), v[5..#v]) \\ Andrew Howroyd, Nov 24 2017


CROSSREFS

Cf. A003447.
Sequence in context: A020044 A024338 A253774 * A229841 A198628 A233020
Adjacent sequences: A003445 A003446 A003447 * A003449 A003450 A003451


KEYWORD

nonn


AUTHOR

N. J. A. Sloane


EXTENSIONS

More terms from Sean A. Irvine, May 13 2015
Name clarified by Andrew Howroyd, Nov 24 2017


STATUS

approved



