Ramsey number $R(7,11)$
The smallest number $n$ such that any two-coloring of the edges of the complete graph $K_n$ must contain either a monochromatic $K_{7}$ in the first color or a monochromatic $K_{11}$ in the second color.
Lower bound:
$405$
Upper bound:
$3197$
Updates
-
2004
Lower bound: $405$
Xu Xiaodong, Xie Zheng, G. Exoo and S.P. Radziszowski, Constructive Lower Bounds on Classical Multicolor Ramsey Numbers, Electronic Journal of Combinatorics, http://www.combinatorics.org, #R35, 11(1) (2004), 24 pages.
[via Small Ramsey Numbers, Stanisław Radziszowski, 2024-09-06] -
2007
Upper bound: $4553$
Huang Yi Ru, Wang Yuandi, Sheng Wancheng, Yang Jiansheng, Zhang Ke Min and Huang Jian, New Upper Bound Formulas with Parameters for Ramsey Numbers, Discrete Mathematics, 307 (2007) 760-763.
[via Small Ramsey Numbers, Stanisław Radziszowski, 2024-09-06] -
2020
Upper bound: $3197$
V. Angeltveit and B.D. McKay, personal communication (2019-2024).
[via Small Ramsey Numbers, Stanisław Radziszowski, 2024-09-06]