Sequence with floatingpoint numbers

[sven-h.simon]

I would like to contribute the following sequence, which I found 
somehow interesting:

3.14159265358979323846,4.18879020478639098461,4.93480220054467930941,
5.26378901391432459671,5.16771278004997002924,4.72476597033140116959,
4.05871212641676821818,3.29850890273870686938,2.55016403987734544385,
1.88410387938990024134,1.33526276885458949587,0.91062875478328314603,
0.59926452932079207688,0.38144328082330448281,0.23533063035889320454,
0.14098110691713903791,0.08214588661112822879,0.04662160103008854577,
0.02580689139001406001

It is the n-dimensional volume of a n-dimensional sphere with radius 1 for
n = 2 to 20. There are some more possible sequences like this.
I find it interesting, but not so interesting to contribute each value as
"important constant".
One way would be to give every a(n) an additional factor of 10**20.
Are there other ways to contribute it as a sequence ?

Sven Simon
Schlossgartenstr. 45
73642 Welzheim
Germany