%I A120669
%S A120669 1,3,8,0,2,1,4,1,8,2,7,4,9,0,7,9,9,0,4,0,0,8,7,5,5,8,1,8,1,4,1,7,0,1,4,
%T A120669 4,0,1,3,9,6,6,6,1,9,9,4,0,0,1,0,2,1,7,4,0,7,6,9,3,1,2,2,7,9,6,9,6,4,0,
%U A120669 3,9,1,1,0,0,9,2,6,8,1,7,8,1,4,1,0,5,7,5,5,1,7,0,3,8,5,0,0,8,9,7,6,3,5
%N A120669 Decimal expansion of arccos(1-8/(Pi^2)).
%C A120669 For a circle with radius r, the measurement in radians of the central 
               angle with endpoints on the circle that are r*4/Pi apart: The average 
               central angle (<= Pi) formed using two randomly chosen points on 
               a circle. The average arc length between such endpoints is r*A120669 
               corresponding to the average chord length r*A088538; so, for the 
               unit circle arc length is A120669 and chord length is A088538.
%e A120669 1.38021418274907990400875581814...
%o A120669 (PARI) acos(1-8/Pi^2)
%Y A120669 Cf. A088538, A120670 (same in degrees), A120671 (A120669/2Pi).
%Y A120669 Sequence in context: A103319 A153021 A155979 this_sequence A021267 A086106 
               A010626
%Y A120669 Adjacent sequences: A120666 A120667 A120668 this_sequence A120670 A120671 
               A120672
%K A120669 cons,nonn
%O A120669 1,2
%A A120669 Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jun 22 2006