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.

A243252 Number of simple connected graphs with n nodes whose fractional chromatic number is equal to its (integer) chromatic number.

This page as a plain text file.
%I A243252 #12 Feb 16 2025 08:33:22
%S A243252 1,1,2,6,20,109,820,10621,244616,10747278
%N A243252 Number of simple connected graphs with n nodes whose fractional chromatic number is equal to its (integer) chromatic number.
%C A243252 This implies that there is no difference between the corresponding integer and linear programs defining fractional colorings. Every simple graph has a fractional chromatic number which is a rational number or integer.
%H A243252 Travis Hoppe and Anna Petrone, <a href="https://github.com/thoppe/Encyclopedia-of-Finite-Graphs">Encyclopedia of Finite Graphs</a>
%H A243252 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ChromaticNumber.html">Chromatic Number</a>
%H A243252 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FractionalChromaticNumber.html">Fractional Chromatic Number</a>
%F A243252 a(n) = A287008(n) - A287007(n).
%Y A243252 Cf. A243251 (fractional chromatic number is not equal to chromatic number).
%Y A243252 Cf. A287007 (not necessarily connected simple graphs with fractional chromatic number equal to chromatic number).
%Y A243252 Cf. A287008 (disconnected simple graphs with fractional chromatic number equal to chromatic number).
%K A243252 nonn,more
%O A243252 1,3
%A A243252 _Travis Hoppe_ and _Anna Petrone_, Jun 20 2014
%E A243252 Name edited by _Michel Marcus_, Jan 12 2025