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A243933 Rounded down ratio of a minimum intersection area with a unit circle area in n-symmetrical unit circles intersect in a single point. 1
17, 5, 77, 17, 210, 40, 445, 77, 812, 133, 1339, 210, 2056, 313, 2991, 445, 4175, 610, 5636, 812, 7403, 1054, 9506, 1339, 11973, 1672, 14835, 2056, 18120, 2494, 21856, 2991, 26075, 3550, 30804, 4175, 36073, 4869 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

Refer to construction rule in article "Circle-Circle Intersection" in MathWorld.

For n > 4, the intersected areas appearing at many sizes. In this case the minimum areas are considered. See illustration in links.

LINKS

Table of n, a(n) for n=3..40.

Kival Ngaokrajang, Illustration of initial terms

Eric Weisstein's World of Mathematics, Circle-Circle Intersection

FORMULA

For n > 2, a(n) = floor(Pi/area), where area = 2*acos(cd/2)-(1/2)*cd*(4-cd^2)^(1/2), cd = 2*sin(((ang*360/n)*Pi/180)/2), ang = floor((n-1)/2).

PROG

(PARI) {for (n=3, 100, ang=floor((n-1)/2); cd=2*sin(((ang*360/n)*Pi/180)/2); area=2*acos(cd/2)-(1/2)*cd*(4-cd^2)^(1/2); print1(floor(Pi/area), ", "))}

CROSSREFS

Sequence in context: A297982 A298631 A338559 * A145965 A040276 A166211

Adjacent sequences:  A243930 A243931 A243932 * A243934 A243935 A243936

KEYWORD

nonn

AUTHOR

Kival Ngaokrajang, Jun 15 2014

STATUS

approved

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Last modified September 22 13:34 EDT 2021. Contains 347607 sequences. (Running on oeis4.)