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%I #7 Feb 14 2018 21:10:57
%S 1,1,3,2,3,4,1,-6,45,-86,173,-100,2641,-48311,717766,-15527527,
%T 395694683,-11210796201,356923346235,-12694851400717,501010779605741,
%U -21827969798073020,1044997258445975691,-54740156237911040100
%N Euler characteristic of mapping class group Gamma_n.
%D Harer, J., The cohomology of the moduli space of curves, Lecture Notes in Math., Vol. 1337, Springer-Verlag, NY, pp. 138-221
%H Sean A. Irvine, <a href="/A007888/b007888.txt">Table of n, a(n) for n = 1..37</a>
%K sign
%O 1,3
%A _Mira Bernstein_
%E More terms from _Sean A. Irvine_, Feb 14 2018