cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A387066 Number of equivalence classes (up to graph homeomorphism) of finite graphs that have an embedding in an orientable surface of genus n which minimally separates the surface of genus n (that is, no proper subset of the embedding separates the genus n surface) but not the surface of genus n-1.

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%I A387066 #9 Aug 18 2025 00:38:56
%S A387066 1,4,21,191,3338,115438
%N A387066 Number of equivalence classes (up to graph homeomorphism) of finite graphs that have an embedding in an orientable surface of genus n which minimally separates the surface of genus n (that is, no proper subset of the embedding separates the genus n surface) but not the surface of genus n-1.
%C A387066 n is called the least separating genus.
%D A387066 C. N. Aagaard and J. J. P. Veerman, Classification of Minimal Separating Sets of Low Genus Surfaces, Topology and its Applications, Accepted, 2025.
%D A387066 J. Bernhard and J. J. P. Veerman, The Topology of Surface Mediatrices, Topology and its Applications, 154, 54-68, 2007.
%e A387066 For genus 0: only the circle.
%e A387066 For genus 1: 2 circles, bouquet of 2 circles, bouquet of 3 circles, 4-fold multi-edge.
%Y A387066 Cf. A384639, A387067, A387068.
%K A387066 nonn,more
%O A387066 0,2
%A A387066 _J. J. P. Veerman_, Aug 15 2025