This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A068353 #19 Jan 21 2025 05:00:39
%S A068353 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 A068353 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 A068353 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 A068353 Decimal expansion of smallest positive root of cos(Pi*x/2)*cosh(Pi*x/2) = -1.
%H A068353 E. A. Harrington, <a href="https://doi.org/10.1364/JOSA.17.000224">The vibrations of tuning-forks</a>, J. Opt. Soc. Am., 17, 224-237 (1928).
%H A068353 G. H. Keulegan, <a href="https://nvlpubs.nist.gov/nistpubs/jres/6/jresv6n4p553_A2b.pdf">On the vibration of U bars</a>, Doctoral dissertation, Johns Hopkins University, 1928.
%H A068353 A. M. Liebetrau, <a href="https://doi.org/10.1111/j.2517-6161.1979.tb01054.x">Some tests of randomness based upon the variance-time curve of the Poisson process</a> Journal of the Royal Statistical Society, Series B (Methodological), 41, September 1979, 32-39.
%e A068353 1.1937283253889343234388...
%t A068353 RealDigits[FindRoot[Cos[Pi x/2]Cosh[Pi x/2]==-1, {x, 1}, WorkingPrecision->200][[1, 2]]][[1]]
%o A068353 (PARI) solve(x=1,2,cos(x)*cosh(x)+1)*2/Pi \\ _Charles R Greathouse IV_, Apr 16 2014
%Y A068353 Equals (2/Pi) times A076417.
%K A068353 nonn,cons
%O A068353 1,3
%A A068353 _Joost de Winter_, Feb 28 2002
%E A068353 Edited by _Dean Hickerson_, Jun 07 2002
%E A068353 Offset corrected by _R. J. Mathar_, Feb 05 2009