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A348461
Size of largest bipartite biregular Moore graph of diameter 4 and degrees n and n.
2
8, 30, 80, 170, 312
OFFSET
2,1
COMMENTS
a(7) >= 516, a(8) = 800, a(9) = 1170, a(10) = 1640.
LINKS
G. Araujo-Pardo, C. Dalfó, M. Á. Fiol and N. López, Bipartite biregular Moore graphs, arXiv:2103.11443 [math.CO], 2021.
G. Araujo-Pardo, C. Dalfó, M. Á. Fiol and N. López, Bipartite biregular Moore graphs, Discrete Math., 334 (2021), # 112582.
FORMULA
Empirical observation: For the terms a(2)-a(6) and a(8)-a(10) a(n) = 2*(A027444(n-1) + 1). It is unknown whether this is also valid for n = 7 and n > 10. - Hugo Pfoertner, Oct 31 2021
Is this the same as 2*A053698(n-1)? If not, where is the first place these sequences differ? - Omar E. Pol, Oct 31 2021
a(n) <= 2*A053698(n-1) (the Moore bound). - Pontus von Brömssen, Oct 31 2021
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Oct 31 2021
STATUS
approved