A005470
Number of unlabeled planar simple graphs with n nodes.
Original entry on oeis.org
1, 1, 2, 4, 11, 33, 142, 822, 6966, 79853, 1140916, 18681008, 333312451
Offset: 0
a(2) = 2 since o o and o-o are the two planar simple graphs on two nodes.
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
- W. T. Trotter, ed., Planar Graphs, Vol. 9, DIMACS Series in Discrete Mathematics and Theoretical Computer Science, Amer. Math. Soc., 1993.
- Turner, James; Kautz, William H. A survey of progress in graph theory in the Soviet Union. SIAM Rev. 12 1970 suppl. iv+68 pp. MR0268074 (42 #2973). See p. 19. - N. J. A. Sloane, Apr 08 2014
- Vetukhnovskii, F. Ya. "Estimate of the Number of Planar Graphs." In Soviet Physics Doklady, vol. 7, pp. 7-9. 1962. - From N. J. A. Sloane, Apr 08 2014
- R. J. Wilson, Introduction to Graph Theory. Academic Press, NY, 1972, p. 162.
- G. Brinkmann, and B. D. McKay, Fast generation of planar graphs, MATCH Commun. Math. Comput. Chem., 58 (2007) 323-357.
- Gunnar Brinkmann and Brendan McKay, plantri and fullgen programs for generation of certain types of planar graph.
- Gunnar Brinkmann and Brendan McKay, plantri and fullgen programs for generation of certain types of planar graph [Cached copy, pdf file only, no active links, with permission]
- E. Friedman, Illustration of small graphs
- N. J. A. Sloane, Transforms
- Eric Weisstein's World of Mathematics, Planar Graph
- Index entries for "core" sequences
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A003094 = Cases[Import["https://oeis.org/A003094/b003094.txt", "Table"], {, }][[All, 2]];
(* EulerTransform is defined in A005195 *)
EulerTransform[Rest @ A003094] (* Jean-François Alcover, Apr 25 2013, updated Mar 17 2020 *)
A003094
Number of unlabeled connected planar simple graphs with n nodes.
Original entry on oeis.org
1, 1, 1, 2, 6, 20, 99, 646, 5974, 71885, 1052805, 17449299, 313372298, 5942258308
Offset: 0
a(3) = 2 since the path o-o-o and the triangle are the two connected planar simple graphs on three nodes.
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
- R. J. Wilson, Introduction to Graph Theory, Academic Press, NY, 1972, p. 162.
- David Wasserman, Brendan McKay and Georg Grasegger, Table of n, a(n) for n = 0..13
- Steven R. Finch, Mathematical Constants II, Encyclopedia of Mathematics and Its Applications, Cambridge University Press, Cambridge, 2018.
- E. Friedman, Illustration of small graphs
- Brendan McKay, Planar graphs
- N. J. A. Sloane, Transforms
- Peter Steinbach, Field Guide to Simple Graphs, Volume 1, Part 17 (For Volumes 1, 2, 3, 4 of this book see A000088, A008406, A000055, A000664, respectively.)
- Eric Weisstein's World of Mathematics, Planar Connected Graph
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a[n_Integer?NonNegative] := a[n] = Module[{m, s, g}, s = Subsets[Range[n], {2}]; m = Length[s]; g = Graph[Range[n], UndirectedEdge @@@ #] & /@ (Pick[s, #, 1] & /@ (IntegerDigits[#, 2, m] & /@ Range[0, 2^m - 1])); Length[DeleteDuplicates[Select[Select[g, ConnectedGraphQ], PlanarGraphQ], IsomorphicGraphQ]]]; Table[a[n], {n, 0, 6}] (* Robert P. P. McKone, Oct 14 2023 *)
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geng -c $n | planarg -q | countg -q # Georg Grasegger, Jul 06 2023
A126100
Number of rooted connected unlabeled graphs on n nodes.
Original entry on oeis.org
0, 1, 1, 3, 11, 58, 407, 4306, 72489, 2111013, 111172234, 10798144310, 1944301471861, 650202565436890, 404697467417019634, 470133531223369393920, 1022561022228933341815171, 4177761667636803276899047351, 32163582481439081597751699343141, 468019937132164016636736323752098741
Offset: 0
For 3 nodes G is either a path (2 kinds of nodes) or a triangle (one kind of node), for a total of a(3) = 3.
For the 5-vertex graphs we have 2 * 1 orbit, 6 * 2 orbits, 8 * 3 orbits, 5 * 4 orbits for a total of 2 + 12 + 24 + 20 = 58.
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permcount[v_] := Module[{m = 1, s = 0, k = 0, t}, For[i = 1, i <= Length[v], i++, t = v[[i]]; k = If[i > 1 && t == v[[i - 1]], k + 1, 1]; m *= t*k; s += t]; s!/m];
edges[v_] := Sum[GCD[v[[i]], v[[j]]], {i, 2, Length[v]}, {j, 1, i - 1}] + Total[Quotient[v, 2]];
g[n_, r_] := (s = 0; Do[s += permcount[p]*(2^(r*Length[p] + edges[p])), {p, IntegerPartitions[n]}]; s/n!);
seq[m_] := Sum[g[n-1, 1] x^(n-1), {n, 0, m}]/Sum[g[n-1, 0] x^(n-1), {n, 0, m}] + O[x]^m // CoefficientList[#, x]& // Prepend[#, 0]&;
seq[20] (* Jean-François Alcover, Jul 09 2018, after Andrew Howroyd *)
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permcount(v) = {my(m=1,s=0,k=0,t); for(i=1,#v,t=v[i]; k=if(i>1&&t==v[i-1],k+1,1); m*=t*k;s+=t); s!/m}
edges(v) = {sum(i=2, #v, sum(j=1, i-1, gcd(v[i],v[j]))) + sum(i=1, #v, v[i]\2)}
g(n,r) = {my(s=0); forpart(p=n, s+=permcount(p)*(2^(r*#p+edges(p)))); s/n!}
seq(n)={concat([0], Vec(Ser(vector(n, n, g(n-1,1)))/Ser(vector(n, n, g(n-1,0)))))} \\ Andrew Howroyd, May 03 2018
A173422
Partials sums of A003094 (unlabeled connected planar simple graphs with n nodes).
Original entry on oeis.org
1, 2, 3, 5, 11, 31, 130, 776, 6750, 78635, 1131440, 18580739, 331953037
Offset: 0
a(11) = 1 + 1 + 1 + 2 + 6 + 20 + 99 + 646 + 5974 + 71885 + 1052805 + 17449299.
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