OFFSET

1,1

COMMENTS

1 + csc(Pi/9) is the radius of the smallest circle into which 11 unit circles can be packed ("r=3.923+ Proved by Melissen in 1994.", according to the Friedman link, which has a diagram). csc(Pi/9) [=1/A019829] is the distance between the center of the larger circle and the center of each unit circle that touches the larger circle.

EXAMPLE

2.9238044001630872522327544133662917...

MATHEMATICA

RealDigits[Csc[20 Degree], 10, 120][[1]] (* Harvey P. Dale, May 27 2023 *)

PROG

(PARI) 1/sin(Pi/9)

CROSSREFS

KEYWORD

cons,nonn

AUTHOR

Rick L. Shepherd, Aug 09 2006

STATUS

approved