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%I #20 Mar 16 2020 02:52:55
%S 1,1,3,8,21,52,132,313,741,1684,3711,7895,16310,32604,63363,119745,
%T 220546,396428,696750,1198812,2022503,3349574,5452496,8732932,
%U 13776366,21423968,32872642,49804323,74560913,110369469,161639227
%N Number of loopless multigraphs with 6 nodes and n edges.
%D CRC Handbook of Combinatorial Designs, 1996, p. 650.
%D F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 88, (4.1.18).
%D J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 517.
%H Andrew Howroyd, <a href="/A014396/b014396.txt">Table of n, a(n) for n = 0..1000</a>
%t CoefficientList[Series[PairGroupIndex[SymmetricGroup[6],s]/.Table[s[i]->1/(1-x^i),{i,1,Binomial[6,2]}],{x,0,30}],x] (* _Geoffrey Critzer_, Oct 14 2012 *)
%o (PARI) concat([1], G(6, 40)) \\ See A191646 for G. - _Andrew Howroyd_, Mar 15 2020
%Y Row 6 of A192517.
%Y Cf. A001399, A003082, A014395, A014397, A014398.
%K nonn
%O 0,3
%A _N. J. A. Sloane_
%E More terms and better description from _Vladeta Jovovic_, Dec 29 1999
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