cp's OEIS Frontend

A244094 Rounded down ratio of area of a unit circle and one of the circles inscribed between a regular n-gon and a circumscribed unit circle.

%I A244094 #12 Jul 03 2014 05:50:17
%S A244094 16,46,109,222,407,690,1099,1669,2437,3445,4737,6363,8376,10834,13797,
%T A244094 17330,21503,26389,32064,38608,46108,54651,64331,75243,87489,101172,
%U A244094 116402,133290,151953,172511,195088,219813,246817,276236,308211,342885,380407,420927,464601,511590
%N A244094 Rounded down ratio of area of a unit circle and one of the  circles inscribed between a regular n-gon and a circumscribed unit circle.
%H A244094 Kival Ngaokrajang, <a href="/A244094/a244094_1.pdf">Illustration of initial terms</a>
%F A244094 a(n) =  floor(Pi/area(n)) where area(n) =  Pi*r(n)^2, r(n) = (1 - cos(Pi/n))/2 = sin(Pi/(2*n))^2, n >= 3.
%o A244094 (PARI)
%o A244094 {
%o A244094   for (n=3, 100,
%o A244094      b=Pi*(n-2)/(2*n);
%o A244094      r=(1-sin(b))/2;
%o A244094      area=Pi*r^2;
%o A244094      a=floor(Pi/area);
%o A244094      print1(a,", ")
%o A244094   )
%o A244094 }
%Y A244094 Cf. A244093, A244096.
%K A244094 nonn,easy
%O A244094 3,1
%A A244094 _Kival Ngaokrajang_, Jun 20 2014
%E A244094 Edited. Formula simplified - _Wolfdieter Lang_, Jun 27 2014