OFFSET
1,1
COMMENTS
It is the spectral radius of the house graph.
LINKS
Alberto Seeger and David Sossa, Infinite families of connected graphs with equal spectral radius, Australas. J. Combin. 87 (2) (2023), 258-276. See p. 270.
Eric Weisstein's World of Mathematics, House Graph
FORMULA
Equals (2 + 10/(3*i*sqrt(111) - 1)^(1/3) + (3*i*sqrt(111) - 1)^(1/3))/3, where i denotes the imaginary unit.
EXAMPLE
2.4811943040920156226335372412168571805527452...
MAPLE
Digits:= 140:
fsolve(x^3-2*x^2-2*x+2)[3]; # Alois P. Heinz, Sep 19 2023
MATHEMATICA
First[RealDigits[Root[#^3-2#^2-2#+2, 3, 0], 10, 88]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Stefano Spezia, Sep 19 2023
STATUS
approved