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A120670

Decimal expansion of 180*arccos(1-8/(Pi^2))/Pi.

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

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OFFSET

2,1

COMMENTS

For a circle with radius r, the measurement in degrees of the central angle with endpoints on the circle that are r*4/Pi apart: The average central angle (<= 180 degrees) 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.

LINKS

Table of n, a(n) for n=2..106.

FORMULA

Equals 180*A120669/Pi = 360*A120671.

EXAMPLE

79.0804474956203908253980311180...

MATHEMATICA

RealDigits[180 ArcCos[1-8/Pi^2]/Pi, 10, 120][[1]] (* Harvey P. Dale, Feb 17 2023 *)

PROG

(PARI) 180*acos(1-8/Pi^2)/Pi

CROSSREFS

Cf. A088538, A120669 (same in radians), A120671 (A120670/360).