A133077 - OEIS

%I #25 Dec 21 2024 05:24:46

%S 6,0,9,3,8,2,8,6,4,0,8,0,7,0,9,6,5,4,6,7,7,7,1,0,1,6,9,5,9,8,6,7,3,6,

%T 3,1,5,0,9,6,8,1,9,5,1,5,8,0,9,9,9,7,6,8,3,4,7,2,5,6,5,4,5,5,4,6,7,2,

%U 7,7,4,1,2,8,3,6,3,3,4,5,0,2,6,0,4,6,4,8,6,1,7,6,7,0,3,2,7,5,4,4,2,1,5,5,0

%N Decimal expansion of smallest disk radius for which five equal disks can cover the unit disk.

%D Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 8.2 p. 484.

%H G. C. Greubel, <a href="/A133077/b133077.txt">Table of n, a(n) for n = 0..5000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/DiskCoveringProblem.html">Disk Covering Problem</a>.

%H <a href="/index/Al#algebraic_08">Index entries for algebraic numbers, degree 8</a>.

%e 0.60938286408070965467...

%t Root[1296*x^8 + 2112*x^7 - 3480*x^6 + 1360*x^5 + 1665*x^4 - 1776*x^3 + 22*x^2 - 800*x + 625, x, 3] // RealDigits[#, 10, 105]& // First (* _Jean-François Alcover_, May 19 2014 *)

%o (PARI)  polrootsreal(1296*x^8 +2112*x^7 -3480*x^6 +1360*x^5 +1665*x^4 -1776*x^3 +22*x^2 -800*x +625)[3] \\ _Charles R Greathouse IV_, Apr 14 2014

%K nonn,cons,changed

%O 0,1

%A _Eric W. Weisstein_, Sep 08 2007