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A040015
Continued fraction for sqrt(20).
5
4, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8
OFFSET
0,1
COMMENTS
Decimal expansion of 212/495. - R. J. Mathar, Aug 25 2025
REFERENCES
Harold Davenport, The Higher Arithmetic, Cambridge University Press, 8th ed., 2008, p. 97.
James J. Tattersall, Elementary Number Theory in Nine Chapters, Cambridge University Press, 1999, page 276.
FORMULA
G.f.: 2*(2 + x + 2*x^2)/(1 - x^2). - Stefano Spezia, Jul 26 2025
EXAMPLE
4.472135954999579392818347337... = 4 + 1/(2 + 1/(8 + 1/(2 + 1/(8 + ...)))). - Harry J. Smith, Jun 03 2009
MAPLE
Digits := 100: convert(evalf(sqrt(N)), confrac, 90, 'cvgts'):
MATHEMATICA
ContinuedFraction[Sqrt[20], 300] (* Vladimir Joseph Stephan Orlovsky, Mar 05 2011 *)
PadRight[{4}, 120, {8, 2}] (* Harvey P. Dale, Jul 17 2023 *)
PROG
(PARI) { allocatemem(932245000); default(realprecision, 26000); x=contfrac(sqrt(20)); for (n=0, 20000, write("b040015.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 03 2009
CROSSREFS
Cf. A010476 (Decimal expansion), A010698.
Sequence in context: A083489 A065464 A201400 * A144926 A153016 A231549
KEYWORD
nonn,cofr,easy
STATUS
approved