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 A068353 Decimal expansion of smallest positive root of cos(Pi x/2) cosh(Pi x/2) = -1. 0
 1, 1, 9, 3, 7, 2, 8, 3, 2, 5, 3, 8, 8, 9, 3, 4, 3, 2, 3, 4, 3, 8, 8, 0, 9, 2, 3, 4, 7, 6, 0, 3, 2, 9, 0, 1, 6, 9, 9, 4, 3, 0, 3, 3, 9, 9, 3, 6, 5, 8, 9, 7, 9, 6, 0, 8, 1, 6, 4, 9, 7, 2, 5, 6, 3, 4, 8, 2, 6, 2, 2, 3, 5, 4, 7, 5, 7, 2, 2, 6, 8, 1, 3, 7, 2, 0, 5, 3, 0, 7, 1, 0, 9, 1, 5, 1, 4, 4, 2, 0, 9, 8, 8, 7, 2 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The root is x = 1.1937283253889343234388... REFERENCES Harrington, E. A. (1928). The vibrations of tuning-forks. JOSA, 17, 224-237. Keulegan, G. H. (1928). On the vibration of U bars (Doctoral dissertation, Johns Hopkins University). Liebetrau, A. M. (1979). Some tests of randomness based upon the variance-time curve of the Poisson process. Journal of the Royal Statistical Society. Series B (Methodological), 41, 32-39. LINKS MATHEMATICA RealDigits[FindRoot[Cos[Pi x/2]Cosh[Pi x/2]==-1, {x, 1}, WorkingPrecision->200][[1, 2]]][[1]] PROG (PARI) solve(x=1, 2, cos(x)*cosh(x)+1)*2/Pi \\ Charles R Greathouse IV, Apr 16 2014 CROSSREFS Equals (2/Pi) times A076417. Sequence in context: A011390 A011229 A324993 * A136251 A073002 A197836 Adjacent sequences:  A068350 A068351 A068352 * A068354 A068355 A068356 KEYWORD nonn,cons AUTHOR Joost de Winter, Feb 28 2002 EXTENSIONS Edited by Dean Hickerson, Jun 07 2002 Offset corrected by R. J. Mathar, Feb 05 2009 STATUS approved

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Last modified September 21 05:55 EDT 2020. Contains 337267 sequences. (Running on oeis4.)