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A290571
Number of dissections of an n-gon into 3- and 5-gons counted up to rotations and reflections.
3
1, 1, 2, 4, 7, 22, 60, 208, 695, 2566, 9451, 36158, 139574, 548347, 2174801, 8719651, 35244472, 143581782, 588858667, 2430036786, 10083626092, 42055927173, 176217259551, 741517642476, 3132564196880, 13281805256068, 56503895845238, 241135999611542
OFFSET
3,3
LINKS
E. Krasko, A. Omelchenko, Brown's Theorem and its Application for Enumeration of Dissections and Planar Trees, The Electronic Journal of Combinatorics, 22 (2015), #P1.17.
EXAMPLE
For a(5) = 2 the dissections of a pentagon are: a dissection into 3 triangles; a dissection into one pentagon.
PROG
(PARI) \\ See A295419 for DissectionsModDihedral().
DissectionsModDihedral(apply(v->v==3||v==5, [1..25])) \\ Andrew Howroyd, Nov 22 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Evgeniy Krasko, Sep 03 2017
EXTENSIONS
Terms a(16) and beyond from Andrew Howroyd, Nov 22 2017
STATUS
approved