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A301484 Decimal expansion of J_0(2)/J_1(2) = 1 - 1/(2 - 1/(3 - 1/(4 - ...))). 2
3, 8, 8, 2, 1, 0, 7, 6, 5, 5, 6, 7, 7, 9, 5, 7, 8, 7, 5, 1, 1, 6, 5, 8, 5, 5, 7, 3, 0, 6, 5, 3, 7, 0, 2, 9, 2, 2, 1, 7, 4, 5, 0, 4, 0, 7, 2, 5, 3, 2, 9, 8, 1, 8, 6, 4, 6, 4, 2, 8, 2, 7, 5, 9, 3, 7, 3, 5, 1, 7, 3, 9, 5, 6, 3, 8, 2, 4, 2, 0, 1, 2, 1, 1, 0, 1, 9, 3, 5, 1, 6, 2, 8, 2, 8, 0, 3, 1, 9, 6, 0, 5, 2, 1, 6 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
These are the first 105 decimal digits of the constant defined by the continued fraction 1 - 1/(2 - 1/(3 - 1/(4 - ... -1/m))) as m goes to infinity. The continued fraction appears to converge fairly rapidly. Just 50 terms, for instance, suffices to produce a numerical value that appears to be good to 100 digits, based on comparisons with more terms and higher precision. This sequence was brought to the author's attention by Beresford Parlett of U.C. Berkeley.
Addendum: This sequence has been identified by Karl Dilcher. He noted that the sequence of continued fraction convergents is the same as A058797. In short, the real constant whose decimal expansion is given above is given by BesselJ[0,2]/BesselJ[1,2] (Mathematica expression). The comments at A058797 have quite a bit of additional information and references.
Equivalent to the imaginary part of the infinite continued fraction i + 1/(2i + 1/(3i + ...)) where i = sqrt(-1). - Matthew Niemiro, Dec 22 2019
LINKS
FORMULA
Equals BesselJ(0,2)/BesselJ(1,2).
EXAMPLE
0.38821076556779578751165855730653702922174504072532981864642827593735174...
MAPLE
evalf(BesselJ(0, 2)/BesselJ(1, 2), 100); # G. C. Greubel, Dec 31 2019
MATHEMATICA
1 +ContinuedFractionK[(-1)^(n+1)*n, {n, 2, Infinity}]
N[1+ContinuedFractionK[(-1)^(n+1)*n, {n, 2, 50}], 105] (* 105 decimals *)
RealDigits[BesselJ[0, 2]/BesselJ[1, 2], 10, 100][[1]] (* G. C. Greubel, Dec 31 2019 *)
PROG
(PARI) default(realprecision, 100); besselj(0, 2)/besselj(1, 2) \\ Altug Alkan, Mar 22 2018
(Magma) SetDefaultRealField(RealField(100)); BesselFunction(0, 2)/BesselFunction(1, 2); // G. C. Greubel, Dec 31 2019
(Sage) numerical_approx(bessel_J(0, 2)/bessel_J(1, 2), digits=100) # G. C. Greubel, Dec 31 2019
CROSSREFS
Sequence in context: A019630 A101749 A206431 * A249451 A019744 A252876
KEYWORD
nonn,cons
AUTHOR
David H Bailey, Mar 22 2018
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)