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A007874 Distinct perimeter lengths of polygons with regularly spaced vertices. 2
1, 1, 1, 2, 4, 10, 24, 63, 177, 428, 1230, 2556, 8202, 18506, 18162, 119069 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

For n points on a circle there are floor(n/2) distinct line segment lengths. Hence an upper bound for a(n) is the number of compositions of n into floor(n/2) nonnegative parts, which is A127040(n-2). To find a(n), the length of A052558(n-2) paths must be computed. - T. D. Noe, Jan 13 2007 [edited by Petros Hadjicostas, Jul 19 2018]

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

Consider n=4. Label the points on the circle A,B,C and D. Suppose that AB has unit length. Then a(4)=2 because the two 4-gons are ABCDA and ACBDA, with perimeters 4 and 2+2*sqrt(2), respectively.

CROSSREFS

Cf. A030077.

Sequence in context: A124499 A303840 A132220 * A294410 A121704 A049144

Adjacent sequences:  A007871 A007872 A007873 * A007875 A007876 A007877

KEYWORD

nonn

AUTHOR

Peter H. Borcherds (p.h.borcherds(AT)bham.ac.uk)

EXTENSIONS

More terms from T. D. Noe, Jan 13 2007

STATUS

approved

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Last modified April 15 01:24 EDT 2021. Contains 342974 sequences. (Running on oeis4.)