login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Table of n, a(n) for n=1..105.

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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