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%I #6 Feb 03 2019 16:03:07
%S 0,1,3,8,20,50,128,326,838,2164,5613,14619,38200,100109,263002,692452,
%T 1826640,4826740,12773610,33850507,89815472,238573535,634359840,
%U 1688317073,4497222961,11988860360,31983701435,85383496739,228083043888
%N Floor of inverse of Minkowski's constant.
%C The subsequence of primes begins: 3, 100109. As a final application of Minkowski's theorem, Stevenhagen shows that the unit group of an order R in a number field with r real and 2s complex embeddings is finitely generated of free rank r + s - 1 (Dirichlet unit theorem).
%H P. Stevenhagen, <a href="http://websites.math.leidenuniv.nl/algebra/ant.pdf">Number Rings</a>, Chapter 5, Geometry of numbers.
%H <a href="http://planetmath.org/encyclopedia/MinkowskisConstant.html">Minkowski's Constant, at Planet Math</a>.
%F a(n) = floor((n^n)*Pi/(4*n!)) = floor((Pi/4)*A000312(n)/A000142(n)).
%e a(0) = floor((1^1)*Pi/(4*1!)) = floor(0.78539816339744830962) = 0.
%e a(10) = floor((10^10)*Pi/(4*10!)) = floor(2164.3467906675714) = 2164.
%p Digits := 200 : A174198 := proc(n) n^n*Pi/4/n! ; floor(%) ; end proc: seq(A174198(n),n=1..30) ; # _R. J. Mathar_, Apr 15 2010
%Y Cf. A000142, A000312.
%K easy,nonn
%O 1,3
%A _Jonathan Vos Post_, Mar 11 2010
%E More terms from _R. J. Mathar_, Apr 15 2010
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