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A348463
Size of largest bipartite biregular Moore graph of diameter 6 and degrees n and n.
2
12, 126, 728, 2730, 7812
OFFSET
2,1
COMMENTS
18660 <= a(7) <= 18662, a(8) = 39216, a(9) = 74898, a(10) = 132860.
Table 3 from these references gives the size of the largest bipartite biregular Moore graph of diameter 3 and degrees n and n, and appears to match 2*A002061.
LINKS
G. Araujo-Pardo, C. Dalfó, M. Á. Fiol and N. López, Bipartite biregular Moore graphs, arXiv:2103.11443 [math.CO], 2021. See Table 2.
G. Araujo-Pardo, C. Dalfó, M. Á. Fiol and N. López, Bipartite biregular Moore graphs, Discrete Math., 334 (2021), # 112582. See Table 3.
FORMULA
Empirical observation: a(n) = 2*(A152031(n-1) + 1) matches terms a(2)-a(6) and a(8)-a(10). - Hugo Pfoertner, Oct 31 2021
a(n) <= 2*A053700(n-1) = 2*(A152031(n-1) + 1) (the Moore bound). - Pontus von Brömssen, Oct 31 2021
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Oct 31 2021
STATUS
approved