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Number of (bidimensional) faces of regular m-polytopes for m >= 3.
2

%I #28 Jan 14 2023 08:46:35

%S 4,6,8,10,12,20,24,32,35,56,80,84,96,120,160,165,220,240,280,286,364,

%T 448,455,560,672,680,720,816,960,969,1140,1200,1320,1330,1540,1760,

%U 1771,1792,2024,2288,2300,2600,2912,2925,3276,3640,3654,4060,4480,4495,4608

%N Number of (bidimensional) faces of regular m-polytopes for m >= 3.

%C In 3 dimensions there are five (convex) regular polytopes and they have 4, 6, 8, 12, or 20 (bidimensional) faces (A053016).

%C In 4 dimensions there are six regular 4-polytopes and they have 10, 24, 32, 96, 720, or 1200 faces (A063925).

%C In m >= 5 dimensions, there are only 3 regular polytopes (i.e., the m-simplex, the m-cube, and the m-crosspolytope) so that we can sort their number of bidimensional faces in ascending order and define the present sequence.

%H Mathematics StackExchange, <a href="https://math.stackexchange.com/questions/833758/what-are-the-formulas-for-the-number-of-vertices-edges-faces-cells-4-faces">What are the formulas for the number of vertices, edges, faces, cells, 4-faces, ..., n-faces, of convex regular polytopes in n≥5 dimensions?</a>

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/List_of_regular_polytopes_and_compounds">List of regular polytopes and compounds</a>

%F {a(n), n >= 1} = {{12, 96, 720, 1200} U {A000292} U {A001788} U {A130809}} \ {0, 1}.

%e 6 is a term since a cube has 6 faces.

%Y Cf. A000292, A001788, A053016, A063925, A130809.

%Y Cf. A359201 (edges), A359662 (cells).

%K easy,nonn

%O 1,1

%A _Marco Ripà_, Dec 20 2022