1,2

Jean Meeus, Wiskunde Post (Belgium), Vol. 10, 1972, pp. 62-63.

T. D. Noe, Table of n, a(n) for n=1..1000

Sascha Kurz, m-gons in regular n-gons

B. Poonen and M. Rubinstein, Number of Intersection Points Made by the Diagonals of a Regular Polygon, SIAM J. Discrete Mathematics, Vol. 11, pp. 135-156.

B. Poonen and M. Rubinstein, The number of intersection points made by the diagonals of a regular polygon, SIAM J. on Discrete Mathematics, Vol. 11, No. 1, 135-156 (1998).

B. Poonen and M. Rubinstein, The number of intersection points made by the diagonals of a regular polygon, arXiv version, which has fewer typos than the SIAM version.

B. Poonen and M. Rubinstein, Mathematica programs for these sequences

Sequences formed by drawing all diagonals in regular polygon

a(n)=A007678(n)+n. - T. D. Noe, Dec 23 2006

del[m_, n_]:=If[Mod[n, m]==0, 1, 0]; R[n_]:=(n^4-6n^3+23n^2-18n+24)/24 + del[2, n](-5n^3+42n^2-40n-48)/48 - del[4, n](3n/4) + del[6, n](-53n^2+310n)/12 + del[12, n](49n/2) + del[18, n]*32n + del[24, n]*19n - del[30, n]*36n - del[42, n]*50n - del[60, n]*190n - del[84, n]*78n - del[90, n]*48n - del[120, n]*78n - del[210, n]*48n; Table[R[n], {n, 1, 1000}] - T. D. Noe (noe(AT)sspectra.com), Dec 21 2006

Sequences related to chords in a circle: A001006, A054726, A006533, A006561, A006600, A007569, A007678. See also entries for chord diagrams in Index file.

Sequence in context: A005305 A125548 A054668 this_sequence A027559 A135492 A027423

Adjacent sequences: A006530 A006531 A006532 this_sequence A006534 A006535 A006536

nonn,easy,nice

njas, Bjorn Poonen (poonen(AT)math.princeton.edu)