A077013 - OEIS

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A077013

Number of different argument values of vector sums generated by n vectors chosen from 2n (equally spaced) points around the unit circle. Arguments are considered different only up to rotation and reflection.

1, 2, 1, 2, 3, 7, 14, 43, 65, 292, 992, 1154

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OFFSET

1,2

COMMENTS

Arg[0] is taken as being equal to 0.

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

The arguments up to rotation and reflection for n=6 are {0, 0.17013, 0.206867, 0.293133, 0.32987, 0.385502, 0.5} or exactly {0, 1/2, 5/2-(6*ArcTan[2])/Pi, 5/2-(6*ArcTan[1+2/Sqrt[3]])/Pi, -3/2-(6*ArcTan[4-3*Sqrt[3]])/Pi, 3/2-(6*ArcTan[6- 3*Sqrt[3]])/Pi, -5/2+(6*ArcTan[4+3*Sqrt[3]])/Pi }

CROSSREFS

Cf. A077078, A006840.

Sequence in context: A082594 A376050 A051850 * A086880 A120405 A252889

Adjacent sequences: A077010 A077011 A077012 * A077014 A077015 A077016

KEYWORD

hard,nonn

AUTHOR

Wouter Meeussen, Nov 28 2002

STATUS

approved