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.

Previous Showing 11-14 of 14 results.

A139673 Number of n X n symmetric binary matrices with all row sums 6.

Original entry on oeis.org

1, 232, 66178, 24243520, 11234051976, 6549149852112, 4762109992158288, 4274712091685443584, 4686484162304929219950, 6209619146419137708859600, 9845751579221258486943505348, 18509102695712474753650903363840, 40904306737052771732376660591663712
Offset: 6

Views

Author

R. H. Hardin, Jun 12 2008

Keywords

Crossrefs

Column k=6 of A333157 and row 6 of A188448.

Extensions

Terms a(13) and beyond from Andrew Howroyd, Mar 09 2020

A139674 Number of n X n symmetric binary matrices with all row sums 7.

Original entry on oeis.org

1, 764, 708256, 805036704, 1127512146540, 1966499966796816, 4274712091685443584, 11528251571501588791296, 38295413179145036856212700, 155411811543624388078758718000, 763997249847515085736557734880512, 4511824317564827934662170498445281792
Offset: 7

Views

Author

R. H. Hardin, Jun 12 2008

Keywords

Crossrefs

Column k=7 of A333157 and row 7 of A188448.

Extensions

Terms a(13) and beyond from Andrew Howroyd, Mar 09 2020

A139675 Number of n X n symmetric binary matrices with all row sums 8.

Original entry on oeis.org

1, 2620, 8372754, 30649435140, 133475706272700, 711040444591249476, 4686484162304929219950, 38295413179145036856212700, 386860001875783390762182911250, 4805622573099374975572752075805000, 72929153106385401417284439399165879652
Offset: 8

Views

Author

R. H. Hardin, Jun 12 2008

Keywords

Crossrefs

Column k=8 of A333157 and row 8 of A188448.

Extensions

Terms a(13) and beyond from Andrew Howroyd, Mar 09 2020

A333158 Irregular triangle read by rows: T(n,k) is the number of k-regular graphs on n labeled nodes with loops allowed, n >= 1, 0 <= k <= n + 1.

Original entry on oeis.org

1, 0, 1, 1, 1, 1, 1, 1, 0, 2, 0, 1, 1, 3, 8, 8, 3, 1, 1, 0, 38, 0, 38, 0, 1, 1, 15, 208, 730, 730, 208, 15, 1, 1, 0, 1348, 0, 20670, 0, 1348, 0, 1, 1, 105, 10126, 188790, 781578, 781578, 188790, 10126, 105, 1, 1, 0, 86174, 0, 37885204, 0, 37885204, 0, 86174, 0, 1
Offset: 1

Views

Author

Andrew Howroyd, Mar 09 2020

Keywords

Comments

A loop adds 2 to the degree of its vertex.

Examples

			Triangle begins:
  1,   0,     1;
  1,   1,     1,      1;
  1,   0,     2,      0,      1;
  1,   3,     8,      8,      3,      1;
  1,   0,    38,      0,     38,      0,      1;
  1,  15,   208,    730,    730,    208,     15,     1;
  1,   0,  1348,      0,  20670,      0,   1348,     0,   1;
  1, 105, 10126, 188790, 781578, 781578, 188790, 10126, 105, 1;
  ...
		

Crossrefs

Row sums are A322635.
Columns k=0..4 are A000012, A123023, A108246, A110039 (with interspersed zeros), A228697.

Formula

T(n,k) = T(n, n+1-k).
Previous Showing 11-14 of 14 results.