A272795 Decimal expansion of 2*sin(1/2).

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

Offset

0,1

Comments

The length of the line underlying an arc of one radian with radius 1 (i.e., the linear distance for ends of an arc length 1 having same length as radius).

Also equals i*e^(-i/2) - i*e^(i/2).

Links

Table of n, a(n) for n=0..86.

Formula

Equals 2*A201504.

Equals Sum_{k>=0} 2*(-1)^k*(1/2 - Pi/2)^(2*k)/(2*k)!. - Ilya Gutkovskiy, May 22 2016

Example

0.958851077208406000546575870431142776163606735881201350377...

Mathematica

RealDigits[2 Sin[1/2], 10, 100][[1]] (* Ilya Gutkovskiy, May 22 2016 *)

Crossrefs

Sequence in context: A351209 A146483 A090463 * A246765 A191759 A289505

Adjacent sequences: A272792 A272793 A272794 * A272796 A272797 A272798

Keyword

nonn,cons

Author

Peter M. Chema, May 22 2016

Extensions

More digits from Jon E. Schoenfield, Mar 15 2018

Status

approved