OFFSET
3,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 3..200
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.
Vladimir Shevelev, On a Luschny question, arXiv:1708.08096 [math.NT], 2017.
EXAMPLE
For a(5) = 2 the dissections of a pentagon are: a dissection into 3 triangles; a dissection into one triangle and one quadrangle.
MATHEMATICA
(* See A295419 for DissectionsModDihedral. *)
DissectionsModDihedral[Boole[# == 3 || # == 4]& /@ Range[1, 30]] (* Jean-François Alcover, Sep 25 2019, after Andrew Howroyd *)
PROG
(PARI) \\ See A295419 for DissectionsModDihedral.
DissectionsModDihedral(apply(v->v==3||v==4, [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