A365910 Minimum number of parts in a partition of all 4-subsets of an n-element set such that the intersection of any two subsets from the same part has size at most 1.
1, 5, 15, 18, 35, 42
Offset: 4
Links
- ArtOfProblemSolving et al., What is the best way to partition the 4-subsets of {1,2,3,...,n}?, MathOverflow, 2020.
- ArtOfProblemSolving et al., What is the best way to partition the 4-subsets of {1,2,3,...,n}?, Mathematics StackExchange, 2020.
Crossrefs
Cf. A004037.
Programs
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Sage
def A365910(n): return Graph([Subsets(n,4), lambda u,v: u!=v and len(u&v)>1]).chromatic_number()
Comments