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A007187 Leech's tree-labeling problem for n nodes.
(Formerly M2532)
1
1, 3, 6, 9, 15, 20, 26, 34, 41 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,2
COMMENTS
a(11) >= 48, a(12) >= 55.
a(n) is the greatest number k such that there exists a tree with n nodes and integral edge labels such that for each integer 1 <= m <= k, there exists a pair of nodes such that the sum of the edge labels on the path connecting the two nodes equals m. - Charlie Neder, Apr 26 2019
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, Sect. C10.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
R. K. Guy, A quarter century of "Monthly" unsolved problems, 1969-1993, Amer Math. Monthly, 100 (1993), 945-949.
J. Leech, On the representation of 1, 2, ..., n by differences, J. Lond. Math. Soc. 31 (1956), 160-169.
CROSSREFS
Cf. A005488.
Sequence in context: A368611 A143981 A031940 * A337502 A082004 A364017
KEYWORD
nonn,hard,nice,more
AUTHOR
STATUS
approved

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Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)