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A290722 Number of dissections of a 2n-gon into polygons with even number of sides counted up to rotations and reflections. 3

%I

%S 1,2,4,13,48,238,1325,8297,54519,373363,2621872,18797682,136969519,

%T 1011903735,7564219361,57129086391,435394899361,3345082819597,

%U 25885718422329,201619294539406,1579629974876090,12442262963919863,98483477967355109,783017782731507416

%N Number of dissections of a 2n-gon into polygons with even number of sides counted up to rotations and reflections.

%H Andrew Howroyd, <a href="/A290722/b290722.txt">Table of n, a(n) for n = 2..200</a>

%H Evgeniy Krasko, Alexander Omelchenko, <a href="http://www.combinatorics.org/ojs/index.php/eljc/article/view/v22i1p17">Brown's Theorem and its Application for Enumeration of Dissections and Planar Trees</a>, The Electronic Journal of Combinatorics, 22 (2015), #P1.17.

%e For a(4) = 4 the dissections of an octagon are: two dissections into 3 quadrangles; a dissection into one hexagon and one quadrangle; a dissection into one octagon.

%o (PARI) \\ See A295419 for DissectionsModDihedral().

%o select(v->v>0, DissectionsModDihedral(apply(v->v%2==0, [1..50]))) \\ _Andrew Howroyd_, Nov 22 2017

%Y Cf. A003168 (counted distinctly).

%Y Cf. A001004, A290816, A295419.

%K nonn

%O 2,2

%A _Evgeniy Krasko_, Sep 03 2017

%E Terms a(8) and beyond from _Andrew Howroyd_, Nov 22 2017

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Last modified November 22 00:32 EST 2019. Contains 329383 sequences. (Running on oeis4.)