

A086201


Decimal expansion of 1/(2*Pi).


30



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

0,2


COMMENTS

If a single hump of cycloid, with arc length 8*radius (generating circle), is inside a rectangle with width=2*radius and length=2*Pi*radius, then the radius must be 1/(2*Pi) (this sequence) to have (2/Pi), A060294, as semi arc of cycloid (arc = 4/Pi = A088538) and the rectangle... length = 1, width = 1/Pi. I suppose that in 3D geometry, gliding along a cycloid, in all directions around, from a point A at the height of 1/Pi, gives Pi*point B.  Eric Desbiaux, Dec 21 2008
Radius of circle having circumference 1.  Clark Kimberling, Jan 06 2014
The number of primitive Pythagorean triangles with hypotenuse less than N is approximately N/(2*Pi), found by Lehmer, cf. Knott link.  Frank Ellermann, Mar 27 2020


LINKS

Table of n, a(n) for n=0..101.
Ron Knott, 9.6 Pythagorean Triples and Pi, 2019.
Eric Weisstein's World of Mathematics, Plouffe's Constants.
Eric Weisstein's World of Mathematics, Pythagorean Triple.
Index entries for transcendental numbers


EXAMPLE

0.15915494309189533576888376337251...


MATHEMATICA

RealDigits[N[1/(2 Pi), 100]][[1]] (* Vladimir Joseph Stephan Orlovsky, Jun 18 2009 *)


PROG

(PARI) 1/(2*Pi) \\ Michel Marcus, Mar 28 2020


CROSSREFS

Cf. A000796 (Pi), A019692 (2*Pi).
Sequence in context: A127414 A186192 A231532 * A010490 A021173 A266553
Adjacent sequences: A086198 A086199 A086200 * A086202 A086203 A086204


KEYWORD

nonn,cons


AUTHOR

Eric W. Weisstein, Jul 12 2003


EXTENSIONS

Link corrected by Fred Daniel Kline, Jul 29 2015


STATUS

approved



