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 A244096 Rounded down area ratio of a circle inscribed in a congruent triangle of a regular n-gon and a circle inscribed between side of such n-gon and a circumscribed unit circle. 3
 0, 4, 9, 18, 30, 45, 63, 84, 108, 135, 166, 200, 237, 277, 321, 367, 417, 471, 527, 587, 649, 716, 785, 858, 933, 1012, 1095, 1180, 1269, 1361, 1456, 1555, 1656, 1761, 1870, 1981, 2096, 2214, 2335, 2459, 2587, 2718, 2852, 2989, 3130, 3274, 3421, 3571, 3725, 3881, 4042 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,2 LINKS Kival Ngaokrajang, Illustration of initial terms FORMULA a(n) = floor((r1(n)/r2(n))^2) where r1(n) = (s(n)/2)*sqrt((2 - s(n))/(2 + s(n))) and r2(n) = (2 - c(n))/4 with s(n) = 2*sin(Pi/n), the side length (length unit 1), and c(n) = 2*cos(Pi/n), the length ratio of the smallest diagonal and the side of a regular n-gon. PROG (PARI) {   for (n=3, 100,      c=2*sin(Pi/n);      s=(2+c)/2;      r1=(((s-1)^2*(s-c))/s)^(1/2);      b=Pi*(n-2)/(2*n);      r2=(1-sin(b))/2;      a=floor(r1^2/r2^2);      print1(a, ", ")   ) } CROSSREFS Cf. A244093, A244094. Sequence in context: A008025 A301196 A008020 * A008146 A038098 A299274 Adjacent sequences:  A244093 A244094 A244095 * A244097 A244098 A244099 KEYWORD nonn AUTHOR Kival Ngaokrajang, Jun 20 2014 EXTENSIONS Edited: Formula rewritten. - Wolfdieter Lang, Jul 02 2014 STATUS approved

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Last modified November 26 01:22 EST 2020. Contains 338631 sequences. (Running on oeis4.)