A006024
Number of labeled mating graphs with n nodes. Also called point-determining graphs.
Original entry on oeis.org
1, 1, 1, 4, 32, 588, 21476, 1551368, 218608712, 60071657408, 32307552561088, 34179798520396032, 71474651351939175424, 296572048493274368856832, 2448649084251501449508762880, 40306353989748719650902623919616
Offset: 0
Consider the square (cycle of length 4) on vertices 1, 2, 3 and 4 in that order. Join a fifth vertex (5) to vertices 1, 3 and 4. The resulting graph is not a mating graph since vertices 1 and 3 both have the set {2, 4, 5} as neighbors. If we delete the edge (1,5) then the resulting graph is a mating graph: the neighborhood sets for vertices 1, 2, 3, 4 and 5 are respectively {2,4}, {1,3}, {2,4,5}, {1,3,5} and {3,4} - all different.
- R. C. Read, The Enumeration of Mating-Type Graphs. Report CORR 89-38, Dept. Combinatorics and Optimization, Univ. Waterloo, 1989.
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
- Andrew Howroyd, Table of n, a(n) for n = 0..50
- I. M. Gessel and J. Li, Enumeration of Point-Determining Graphs, arXiv:0705.0042 [math.CO], 2007-2009.
- I. M. Gessel and J. Li, Enumeration of point-determining graphs, J. Combinatorial Theory Ser. A 118 (2011), 591-612.
- R. C. Read, The Enumeration of Mating-Type Graphs, Dept. Combinatorics and Optimization, Univ. Waterloo, Oct 1989. (Annotated scanned copy)
- D. Sumner, Point determination in graphs, Discrete Mathematics 5 (1973), 179-187.
-
a[n_] := Sum[StirlingS1[n, k] 2^Binomial[k, 2], {k, 0, n}];
Array[a, 15] (* Jean-François Alcover, Jul 25 2018 *)
-
a(n)=n!*polcoeff(sum(k=0,n,2^(k*(k-1)/2)*log(1+x+x*O(x^n))^k/k!),n) \\ Paul D. Hanna, May 20 2009
A079307
Number of n-node labeled mating digraphs whose complements are connected.
Original entry on oeis.org
1, 2, 47, 3537, 990504, 1052216730, 4368243719790, 71899754628285990, 4719127231162959826680, 1237680394434222243386835240, 1297992518900121521819851167607200
Offset: 1
A092430
Number of n-node labeled connected mating graphs, cf. A006024.
Original entry on oeis.org
1, 1, 25, 438, 18388, 1409674, 206682994, 58152537184, 31715884061624, 33827568738189576, 71066571962396085656, 295645506683051376527648, 2444503529745123474354656720, 40269655263141217619453414445968
Offset: 2
- Goran Kilibarda, "Enumeration of unlabeled mating graphs", Belgrade, 2004, to be published.
-
a(n)={n!*polcoef(log(sum(i=0, n, 2^binomial(i, 2)*log(1+x + O(x*x^n))^i/i!)/(1+x)), n)} \\ Andrew Howroyd, Sep 09 2018
A129584
Number of unlabeled bi-point-determining graphs: graphs in which no two vertices have the same neighborhoods or the same augmented neighborhoods (the augmented neighborhood of a vertex is the neighborhood of the vertex union the vertex itself).
Original entry on oeis.org
1, 0, 0, 1, 6, 36, 324, 5280, 156088, 8415760
Offset: 1
Ji Li (vieplivee(AT)hotmail.com), May 07 2007
A129583
Number of labeled bi-point-determining graphs with n vertices.
Original entry on oeis.org
1, 1, 0, 0, 12, 312, 13824, 1147488, 178672128, 52666091712, 29715982846848, 32452221242518272, 69259424722321036032, 291060255757818125657088, 2421848956937579216663491584, 40050322614433939228627991906304, 1319551659023608317386779165849208832
Offset: 0
Ji Li (vieplivee(AT)hotmail.com), May 07 2007
- R. C. Read, The Enumeration of Mating-Type Graphs. Report CORR 89-38, Dept. Combinatorics and Optimization, Univ. Waterloo, 1989.
-
seq(n)={my(g=sum(k=0, n, 2^binomial(k,2)*x^k/k!) + O(x*x^n)); Vec(serlaplace(subst(g, x, 2*log(1+x+O(x*x^n))-x)))} \\ Andrew Howroyd, May 06 2021
a(0)=1 prepended and terms a(13) and beyond from
Andrew Howroyd, May 06 2021
A129585
Number of labeled connected bi-point-determining graphs with n vertices (see A129583).
Original entry on oeis.org
1, 1, 0, 0, 12, 252, 12312, 1061304, 170176656, 51134075424, 29204599254624, 32130964585236096, 68873851786953047040, 290164895151435531345024, 2417786648013402212500060416, 40014055814155246577685250570752, 1318911434129029730677931158374449664
Offset: 0
Ji Li (vieplivee(AT)hotmail.com), May 07 2007
-
max = 15; f[x_] := x + Log[ Sum[ 2^Binomial[n, 2]*((2*Log[1 + x] - x)^n/n!), {n, 0, max}]/(1 + x)]; A129585 = Drop[ CoefficientList[ Series[ f[x], {x, 0, max}], x]*Range[0, max]!, 1](* Jean-François Alcover, Jan 13 2012, after e.g.f. *)
-
seq(n)={my(g=sum(k=0, n, 2^binomial(k,2)*x^k/k!) + O(x*x^n)); Vec(serlaplace(1+x+log(subst(g, x, 2*log(1+x+O(x*x^n))-x)/(1+x))))} \\ Andrew Howroyd, May 06 2021
a(0)=1 prepended and terms a(16) and beyond from
Andrew Howroyd, May 06 2021
A129586
Number of unlabeled connected bi-point-determining graphs (see A129583).
Original entry on oeis.org
1, 0, 0, 1, 5, 31, 293, 4986, 151096, 8264613, 812528493, 144251345591, 46649058611515, 27744159658789435, 30603223477819571330, 63039669933956074333128, 243839768084859914114367906, 1779006737976575676931317142360, 24571827603944282248499044846893618
Offset: 1
Ji Li (vieplivee(AT)hotmail.com), May 07 2007
- Martin Rubey, Table of n, a(n) for n = 1..29
- Florian Fürnsinn, Moritz Gangl, and Martin Rubey, Unexpectedly, a symmetry on unlabeled graphs, arXiv:2505.03665 [math.CO], 2025. See p. 18.
- Ira M. Gessel and Ji Li, Enumeration of point-determining Graphs, Journal of Combinatorial Theory, Series A 118 (2011) 591-612.
Showing 1-7 of 7 results.
Comments