OFFSET
0,1
COMMENTS
This is also the decimal expansion of the real root of y^3 - y/12 - 53/108, that is, 0.8239647728..., after subtraction of 1/6. - Wolfdieter Lang, Aug 18 2022
LINKS
G. Chen et al., Second neighborhood via first neighborhood in digraphs, Annals Combin., 7 (2000), 15-20.
FORMULA
From Wolfdieter Lang, Aug 18 2022: (Start)
Equals ((53 + 6*sqrt(78))^(1/3) + 1/(53 + 6*sqrt(78))^(1/3) - 1)/6.
Equals ((53 + 6*sqrt(78))^(1/3) + (53 - 6*sqrt(78))^(1/3) - 1)/6. (End)
EXAMPLE
0.65729810613837599082505552...
MATHEMATICA
RealDigits[x/.Solve[2x^3+x^2-1==0, x][[1]], 10, 120][[1]] (* Harvey P. Dale, Jun 03 2017 *)
RealDigits[Root[2*x^3+x^2-1, 1], 10, 120][[1]] (* Harvey P. Dale, Mar 04 2023 *)
PROG
(PARI) real(polroots(2*x^3+x^2-1)[1]) \\ Charles R Greathouse IV, Mar 25 2014
(PARI) polrootsreal(2*x^3+x^2-1)[1] \\ Charles R Greathouse IV, Oct 27 2023
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
N. J. A. Sloane, Jan 18 2004
STATUS
approved