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A218802 Decimal expansion of largest x such that x^2 = Gamma(x+1). 2
3, 5, 6, 2, 3, 8, 2, 2, 8, 5, 3, 9, 0, 8, 9, 7, 6, 9, 1, 4, 1, 5, 6, 4, 4, 3, 4, 2, 7, 4, 7, 6, 1, 0, 3, 1, 1, 7, 8, 1, 1, 0, 6, 4, 7, 5, 0, 9, 7, 2, 1, 6, 1, 9, 4, 3, 3, 7, 9, 2, 0, 3, 1, 1, 7, 0, 0, 5, 4, 1, 6, 7, 6, 5, 0, 8, 5, 5, 6, 5, 6, 0, 2, 6, 5, 4, 7, 6, 3, 8, 8, 6, 4, 5, 0, 9, 2, 4, 0, 2, 3, 6, 0, 2, 6, 3, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
In other words, the largest number whose square and factorial coincide.
As one knows from the famous illustration in Jahnke and Emde (p. 13) (or Abramowitz and Stegun, p. 255), there are infinitely many solutions to x^2 = x!. For example, there is another solution near -1.8065. - N. J. A. Sloane, Dec 24 2012
Decimal expansion of greatest real fixed point of Gamma(x). (The only other positive fixed point is 1.) - Rick L. Shepherd, Feb 24 2014
The interval (c, x) = (0.2541970697269031..., 3.562382285390897691415...) with Gamma(c) = x = Gamma(x) is the interval of convergence to 1 of the iteration x->Gamma(x). - Andrea Pinos, Jul 06 2023
REFERENCES
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 255.
Eugene Jahnke and Fritz Emde, Table of Functions with Formulae and Curves, Dover Book, New York, 1945, page 13.
LINKS
EXAMPLE
3.562382285390897691415...
MAPLE
Digits:= 150:
s:= convert(fsolve(x^2 = GAMMA(x+1), x=7/2)/10, string):
seq(parse(s[n+1]), n=1..120); # Alois P. Heinz, Dec 26 2012
MATHEMATICA
RealDigits[x /. FindRoot[x^2 == Gamma[x + 1], {x, 3}, WorkingPrecision -> 100]][[1]] (* Bruno Berselli, Dec 24 2012 *)
PROG
(PARI) solve(x=3, 4, x^2-gamma(x+1)) \\ Charles R Greathouse IV, Dec 26 2012
(PARI) solve(x=3, 4, x-gamma(x)) \\ Rick L. Shepherd, Feb 24 2014
CROSSREFS
Sequence in context: A178255 A154467 A152713 * A236101 A203802 A306554
KEYWORD
nonn,cons
AUTHOR
Marshes Skutnik, Nov 06 2012
STATUS
approved

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Last modified May 8 23:08 EDT 2024. Contains 372341 sequences. (Running on oeis4.)