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%I #15 Jun 24 2014 01:08:22
%S 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,
%T 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,
%U 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
%N Decimal expansion of smallest positive root of cos(Pi x/2) cosh(Pi x/2) = -1.
%C The root is x = 1.1937283253889343234388...
%D Harrington, E. A. (1928). The vibrations of tuning-forks. JOSA, 17, 224-237.
%D Keulegan, G. H. (1928). On the vibration of U bars (Doctoral dissertation, Johns Hopkins University).
%D 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.
%t RealDigits[FindRoot[Cos[Pi x/2]Cosh[Pi x/2]==-1, {x, 1}, WorkingPrecision->200][[1, 2]]][[1]]
%o (PARI) solve(x=1,2,cos(x)*cosh(x)+1)*2/Pi \\ _Charles R Greathouse IV_, Apr 16 2014
%Y Equals (2/Pi) times A076417.
%K nonn,cons
%O 1,3
%A _Joost de Winter_, Feb 28 2002
%E Edited by _Dean Hickerson_, Jun 07 2002
%E Offset corrected by _R. J. Mathar_, Feb 05 2009
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