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.

Showing 1-5 of 5 results.

A294525 Triangle read by rows: T(n,k) is the number of simple connected graphs on n nodes with k center nodes.

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 2, 2, 0, 2, 8, 4, 4, 0, 5, 29, 19, 18, 18, 0, 28, 180, 84, 119, 118, 129, 0, 223, 1463, 821, 1055, 1426, 1390, 1811, 0, 3151, 20093, 12485, 17297, 24853, 29987, 30515, 46177, 0, 79673, 474063, 343572, 486446, 763319, 1015304, 1247381, 1296986, 2235630, 0, 3853870
Offset: 1

Views

Author

Andrew Howroyd, Nov 01 2017

Keywords

Comments

The column sequences A052437-A052441 also include disconnected graphs. Disconnected graphs have an infinite radius and all nodes are considered a part of the center.

Examples

			Triangle begins:
:    1;
:    0,   1;
:    1,   0,    1;
:    2,   2,    0,    2;
:    8,   4,    4,    0,    5;
:   29,  19,   18,   18,    0,   28;
:  180,  84,  119,  118,  129,    0, 223;
: 1463, 821, 1055, 1426, 1390, 1811,   0, 3151;
...

Links

Crossrefs

Columns 1..5 except first term are A052437, A052438, A052439, A052440, A052441.
Row sums give A001349.

A052438 Number of simple unlabeled n-node graphs with 2 center nodes.

Original entry on oeis.org

0, 2, 0, 2, 4, 19, 84, 821, 12485, 343572, 16164685, 1289300669
Offset: 1

Views

Author

Eric W. Weisstein

Keywords

Links

Crossrefs

Column 2 of A294525 for n > 2.
Cf. A052437, A052439, A052440, A052441.

Extensions

a(8)-a(10) from Andrew Howroyd, Nov 02 2017
a(11)-a(12) from Sean A. Irvine, Nov 23 2021

A052439 Number of simple unlabeled n-node graphs with 3 center nodes.

Original entry on oeis.org

0, 0, 3, 0, 4, 18, 119, 1055, 17297, 486446, 24269709, 2095669951
Offset: 1

Views

Author

Eric W. Weisstein

Keywords

Links

Crossrefs

Column 3 of A294525 for n > 3.
Cf. A052437, A052438, A052440, A052441.

Extensions

a(8)-a(10) from Andrew Howroyd, Nov 02 2017
a(11)-a(12) from Sean A. Irvine, Nov 23 2021

A052440 Number of simple unlabeled n-node graphs with 4 center nodes.

Original entry on oeis.org

0, 0, 0, 7, 0, 18, 118, 1426, 24853, 763319, 39773455, 3569963990
Offset: 1

Views

Author

Eric W. Weisstein

Keywords

Links

Crossrefs

Column 4 of A294525 for n > 4.
Cf. A052437, A052438, A052439, A052441.

Extensions

a(8)-a(10) from Andrew Howroyd, Nov 02 2017
a(11)-a(12) from Sean A. Irvine, Nov 23 2021

A052441 Number of simple unlabeled n-node graphs with 5 center nodes.

Original entry on oeis.org

0, 0, 0, 0, 18, 0, 129, 1390, 29987, 1015304, 59286916, 5764417079
Offset: 1

Views

Author

Eric W. Weisstein

Keywords

Links

Crossrefs

Column 5 of A294525 for n > 5.
Cf. A052437, A052438, A052439, A052440.

Extensions

a(8)-a(10) from Andrew Howroyd, Nov 02 2017
a(11)-a(12) from Sean A. Irvine, Nov 23 2021
Showing 1-5 of 5 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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