cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A241464 Number of simple connected graphs g on n nodes with |Aut(g)| = 36.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 3, 16, 132, 1341
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A241465 Number of simple connected graphs g on n nodes with |Aut(g)| = 48.

Original entry on oeis.org

0, 0, 0, 0, 0, 4, 14, 65, 504, 5215
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A241466 Number of simple connected graphs g on n nodes with |Aut(g)| = 72.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 2, 16, 124, 1070
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A241467 Number of simple connected graphs g on n nodes with |Aut(g)| = 120.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 1, 5, 21, 211
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A241468 Number of simple connected graphs g on n nodes with |Aut(g)| = 144.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 3, 12, 51, 477
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A241469 Number of simple connected graphs g on n nodes with |Aut(g)| = 240.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 3, 8, 51, 336
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A241470 Number of simple connected graphs g on n nodes with |Aut(g)| = 720.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 1, 4, 13, 60
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A241471 Number of simple connected graphs g on n nodes with |Aut(g)| = 5040.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 1, 1, 5
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Apr 25 2014

Keywords

Crossrefs

Cf. Values of |Aut(g)| for simple connected graphs, A124059, A241454, A241455, A241456, A241457, A241458, A241459, A241460, A241461, A241462, A241463, A241464, A241465, A241466, A241467, A241468, A241469, A241470, A241471.

A368598 Number of non-isomorphic n-element sets of singletons or pairs of elements of {1..n}, or unlabeled loop-graphs with n edges and up to n vertices.

Original entry on oeis.org

1, 1, 2, 6, 17, 52, 173, 585, 2064, 7520, 28265, 109501, 437394, 1799843, 7629463, 33302834, 149633151, 691702799, 3287804961, 16058229900, 80533510224, 414384339438, 2185878202630, 11811050484851, 65318772618624, 369428031895444, 2135166786135671, 12601624505404858
Offset: 0

Views

Author

Gus Wiseman, Jan 05 2024

Keywords

Comments

It doesn't matter for this sequence whether we use loops such as {x,x} or half-loops such as {x}.

Examples

			Non-isomorphic representatives of the a(0) = 1 through a(4) = 17 set-systems:
  {}  {{1}}  {{1},{2}}    {{1},{2},{3}}        {{1},{2},{3},{4}}
             {{1},{1,2}}  {{1},{2},{1,2}}      {{1},{2},{3},{1,2}}
                          {{1},{2},{1,3}}      {{1},{2},{3},{1,4}}
                          {{1},{1,2},{1,3}}    {{1},{2},{1,2},{1,3}}
                          {{1},{1,2},{2,3}}    {{1},{2},{1,2},{3,4}}
                          {{1,2},{1,3},{2,3}}  {{1},{2},{1,3},{1,4}}
                                               {{1},{2},{1,3},{2,3}}
                                               {{1},{2},{1,3},{2,4}}
                                               {{1},{3},{1,2},{2,4}}
                                               {{1},{1,2},{1,3},{1,4}}
                                               {{1},{1,2},{1,3},{2,3}}
                                               {{1},{1,2},{1,3},{2,4}}
                                               {{1},{1,2},{2,3},{3,4}}
                                               {{2},{1,2},{1,3},{1,4}}
                                               {{4},{1,2},{1,3},{2,3}}
                                               {{1,2},{1,3},{1,4},{2,3}}
                                               {{1,2},{1,3},{2,4},{3,4}}
		

Crossrefs

For any number of edges of any size we have A000612, covering A055621.
For any number of edges we have A000666, A054921, A322700.
The labeled version is A014068.
Counting by weight gives A320663, or A339888 with loops {x,x}.
The covering case is A368599.
For edges of any size we have A368731, covering A368186.
Row sums of A368836.
A000085 counts set partitions into singletons or pairs.
A001515 counts length-n set partitions into singletons or pairs.
A100861 counts set partitions into singletons or pairs by number of pairs.
A111924 counts set partitions into singletons or pairs by length.

Programs

  • Mathematica
    brute[m_]:=First[Sort[Table[Sort[Sort /@ (m/.Rule@@@Table[{(Union@@m)[[i]],p[[i]]}, {i,Length[p]}])], {p,Permutations[Range[Length[Union@@m]]]}]]];
    Table[Length[Union[brute /@ Subsets[Subsets[Range[n],{1,2}],{n}]]],{n,0,5}]
  • PARI
    a(n) = polcoef(G(n, O(x*x^n)), n) \\ G defined in A070166. - Andrew Howroyd, Jan 09 2024

Formula

a(n) = A070166(n, n). - Andrew Howroyd, Jan 09 2024

Extensions

Terms a(7) and beyond from Andrew Howroyd, Jan 09 2024

A003400 Number of asymmetric (not necessarily connected) graphs with n nodes.

Original entry on oeis.org

1, 0, 0, 0, 0, 8, 152, 3696, 135004, 7971848, 805364776, 144123121972
Offset: 1

Views

Author

Keywords

Comments

Number of simple graphs g on n nodes with |Aut(g)| = 1.

References

  • F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 220, Section P3.4.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A124059 (connected simple asymmetric graphs).
Cf. A275867 (disconnected simple asymmetric graphs).
Cf. A000088 (simple graphs).

Programs

  • nauty
    for n in {1..10}; do geng -q ${n} | countg -q -a1 | grep altogether | awk '{print $1}'; done # - Sean A. Irvine, Apr 22 2015

Formula

a(n) = A124059(n) + A275867(n).

Extensions

a(8) and a(9) from Eric W. Weisstein, Jun 09 2004
a(10) and a(11) from Zoran Maksimovic, Vladeta Jovovic, Jan 21 2005
a(12) from Sean A. Irvine, Apr 22 2015
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