cp's OEIS Frontend

A199394 The number of ways to color the vertices of all (11) simple unlabeled graphs on 4 nodes using at most n colors.

%I A199394 #16 Sep 23 2013 09:54:11
%S A199394 11,90,357,996,2255,4446,7945,13192,20691,31010,44781,62700,85527,
%T A199394 114086,149265,192016,243355,304362,376181,460020,557151,668910,
%U A199394 796697,941976,1106275,1291186,1498365,1729532,1986471,2271030,2585121,2930720,3309867,3724666
%N A199394 The number of ways to color the vertices of all (11) simple unlabeled graphs on 4 nodes using at most n colors.
%H A199394 Vincenzo Librandi, <a href="/A199394/b199394.txt">Table of n, a(n) for n = 1..1000</a>
%F A199394 a(n)= 8*n^4/3 + 4*n^3 + 10*n^2/3 + n.
%F A199394 G.f.: -x*(x^3+17*x^2+35*x+11) / (x-1)^5. - _Colin Barker_, Sep 22 2013
%t A199394 Table[Total[Table[CycleIndex[GraphData[{4,k}, "Automorphisms"], s], {k, 1,11}] /. Table[s[i]-> n, {i, 1, 4}]], {n, 1, 25}]
%o A199394 (PARI) Vec(-x*(x^3+17*x^2+35*x+11)/(x-1)^5  + O(x^100)) \\ _Colin Barker_, Sep 22 2013
%Y A199394 Cf. A002492 (3 nodes).
%K A199394 nonn,easy
%O A199394 1,1
%A A199394 _Geoffrey Critzer_, Nov 05 2011
%E A199394 More terms from _Colin Barker_, Sep 22 2013
%E A199394 Added a(4) = 996 from _Vincenzo Librandi_, Sep 23 2013