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 1-8 of 8 results.

A139685 Number of n X n symmetric binary matrices with no row sum greater than 9.

Original entry on oeis.org

1, 2, 8, 64, 1024, 32768, 2097152, 268435456, 68719476736, 35184372088832, 35680013894626133, 69256173251646457490, 241954801784975938299853, 1412334943658808490059334190, 12845700351286288760264255058879, 171982565320546482600201655399505478
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=9 of A334548.

Extensions

Terms a(13) and beyond from Andrew Howroyd, May 08 2020

A139678 Number of n X n symmetric binary matrices with no row sum greater than 2.

Original entry on oeis.org

1, 2, 8, 45, 315, 2634, 25518, 280257, 3434595, 46400310, 684374076, 10933866027, 187983528813, 3458845917990, 67787903801790, 1409293876400019, 30968525550983913, 717023025711440082, 17442766619178969600, 444704318660973471885, 11855331996299677291131
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=2 of A334548.

Programs

  • Maple
    n:=18: G:=taylor((1/sqrt(1-x))*exp((6*x + x^2 + x^3)/(4 - 4*x)),x=0,n+1): seq(coeff(G,x,m)*m!,m=0..n); # Nathaniel Johnston, Apr 19 2011
  • PARI
    seq(n) = {Vec(serlaplace(exp( (6*x + x^2 + x^3)/(4*(1 - x)) + O(x*x^n) ) / sqrt(1 - x + O(x*x^n))))} \\ Andrew Howroyd, May 08 2020

Formula

E.g.f.: exp( (6*x + x^2 + x^3)/(4*(1 - x)) ) / sqrt(1 - x). - Joel B. Lewis, Apr 17 2011, corrected by Vaclav Kotesovec, Aug 13 2013
a(n) ~ n^n*exp(2*sqrt(2*n)-n-7/4)/sqrt(2) * (1+17/(6*sqrt(2*n))). - Vaclav Kotesovec, Aug 13 2013
Recurrence: 2*a(n) = 4*n*a(n-1) - 2*(n-2)*(n-1)*a(n-2) + (n-2)*(n-1)*a(n-3) - (n-3)*(n-2)*(n-1)*a(n-4). - Vaclav Kotesovec, Aug 13 2013

Extensions

a(19)-a(20) added from b-file by Andrew Howroyd, May 08 2020

A139679 Number of n X n symmetric binary matrices with no row sum greater than 3.

Original entry on oeis.org

1, 2, 8, 64, 809, 13846, 301262, 8035168, 255780779, 9519891214, 407613033836, 19816627136912, 1082142442901863, 65776576008442274, 4416031241930248774, 325289604104049686096, 26137255635911145802777, 2279186202842678350137218, 214713550195887533572753024
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=3 of A334548.

Extensions

Terms a(13) and beyond from Andrew Howroyd, May 08 2020

A139680 Number of n X n symmetric binary matrices with no row sum greater than 4.

Original entry on oeis.org

1, 2, 8, 64, 1024, 28217, 1146419, 62951431, 4451407563, 392447922178, 42102440864054, 5391561047209898, 811314950514676762, 141599096294933832181, 28348376853054890615951, 6448749608634353498219753, 1653216120840296892595307251, 474197636984335589673286631814
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=4 of A334548.

Extensions

Terms a(13) and beyond from Andrew Howroyd, May 08 2020

A139681 Number of n X n symmetric binary matrices with no row sum greater than 5.

Original entry on oeis.org

1, 2, 8, 64, 1024, 32768, 1914733, 178499118, 23973965155, 4356864886906, 1028823851939030, 306635655405986312, 112789704243814005142, 50281311185009713150048, 26760450115727957945767409, 16787646103442094018698106106, 12278130772483524854754380090307
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=5 of A334548.

Extensions

Terms a(13) and beyond from Andrew Howroyd, May 08 2020

A139682 Number of n X n symmetric binary matrices with no row sum greater than 6.

Original entry on oeis.org

1, 2, 8, 64, 1024, 32768, 2097152, 254409765, 52635426489, 16734894319214, 7584366191600668, 4658699927786935270, 3743721825782942609558, 3832881704712490758507152, 4895883231714885655148797216, 7669344273849107780888127116263, 14522102432152504473007144076157867
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=6 of A334548.

A139683 Number of n X n symmetric binary matrices with no row sum greater than 7.

Original entry on oeis.org

1, 2, 8, 64, 1024, 32768, 2097152, 268435456, 66628946641, 29707592691510, 21634670753754060, 23709506474859569328, 36821021837919664452090, 77635187673471762914463552, 215313862348697780762374273824, 766493362781127793638943080523776
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=7 of A334548.

Extensions

Terms a(13) and beyond from Andrew Howroyd, May 08 2020

A139684 Number of n X n symmetric binary matrices with no row sum greater than 8.

Original entry on oeis.org

1, 2, 8, 64, 1024, 32768, 2097152, 268435456, 68719476736, 34575388318705, 32448313431713405, 52469561348291720657, 134755962211702695614887, 514006997326078783646604259, 2768435750908792178769980837441, 20276667790903553518295082198527981
Offset: 0

Views

Author

R. H. Hardin, Jun 13 2008

Keywords

Crossrefs

Column k=8 of A334548.

Extensions

Terms a(13) and beyond from Andrew Howroyd, May 08 2020
Showing 1-8 of 8 results.