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 1-10 of 12 results. Next

A216332 Number of horizontal and antidiagonal neighbor colorings of the even squares of an n X 2 array with new integer colors introduced in row major order.

Original entry on oeis.org

1, 2, 3, 10, 27, 114, 409, 2066, 9089, 52922, 272947, 1788850, 10515147, 76282138, 501178937, 3974779402, 28773452321, 247083681522, 1949230218691, 17984917069018, 153281759047387, 1510073008031682, 13806215066685433
Offset: 1

Views

Author

R. H. Hardin, Sep 04 2012

Keywords

Comments

Number of vertex covers and independent vertex sets of the n-1 X n-1 black bishops graph. Equivalently, the number of ways to place any number of non-attacking bishops on the black squares of an n-1 X n-1 board. - Andrew Howroyd, May 08 2017

Examples

			Some solutions for n=5:
..0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x
..x..1....x..1....x..1....x..0....x..1....x..1....x..0....x..1....x..1....x..0
..0..x....2..x....2..x....1..x....2..x....2..x....1..x....2..x....0..x....1..x
..x..2....x..0....x..1....x..2....x..1....x..0....x..1....x..0....x..1....x..2
..3..x....3..x....3..x....0..x....2..x....1..x....0..x....2..x....0..x....3..x
There are 5 black squares on a 3 X 3 board. There is 1 way to place no non-attacking bishops, 5 ways to place 1 and 4 ways to place 2 so a(4)=1+5+4=10. - _Andrew Howroyd_, Jun 06 2017
		

Crossrefs

Column 2 of A216338.
Row sums of A274105(n-1) for n>2.

Programs

  • Mathematica
    Table[Sum[Binomial[Ceiling[n/2], k] BellB[n - k], {k, 0, Ceiling[n/2]}], {n, 0, 20}] (* Eric W. Weisstein, Jun 25 2017 *)

A216333 Number of horizontal and antidiagonal neighbor colorings of the even squares of an nX3 array with new integer colors introduced in row major order.

Original entry on oeis.org

1, 2, 15, 52, 877, 4140, 115975, 678570, 27644437, 190899322, 10480142147, 82864869804, 5832742205057, 51724158235372, 4506715738447323, 44152005855084346, 4638590332229999353, 49631246523618756274
Offset: 1

Views

Author

R. H. Hardin Sep 04 2012

Keywords

Comments

Column 3 of A216338

Examples

			Some solutions for n=4
..0..x..1....0..x..1....0..x..1....0..x..1....0..x..1....0..x..1....0..x..1
..x..2..x....x..2..x....x..2..x....x..0..x....x..2..x....x..2..x....x..2..x
..3..x..0....3..x..1....1..x..2....2..x..0....3..x..2....1..x..0....3..x..4
..x..1..x....x..3..x....x..3..x....x..3..x....x..4..x....x..1..x....x..5..x
		

A216334 Number of horizontal and antidiagonal neighbor colorings of the even squares of an n X 4 array with new integer colors introduced in row major order.

Original entry on oeis.org

1, 5, 42, 726, 15144, 502658, 18378580, 950376664, 52183667212, 3788883495864, 286529186194664, 27420871472654064, 2701657928740913416, 326508788572113365896, 40316833236311531705440, 5965422648942609379676752, 897057171450298448594594368, 158723597386944654236759074832
Offset: 1

Views

Author

R. H. Hardin, Sep 04 2012

Keywords

Examples

			Some solutions for n=4:
..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
..x..2..x..1....x..0..x..1....x..2..x..0....x..2..x..3....x..2..x..0
..1..x..2..x....2..x..3..x....0..x..3..x....3..x..4..x....0..x..3..x
..x..1..x..2....x..0..x..1....x..0..x..3....x..5..x..3....x..1..x..4
		

Crossrefs

Column 4 of A216338.

A216335 Number of horizontal and antidiagonal neighbor colorings of the even squares of an n X 5 array with new integer colors introduced in row major order.

Original entry on oeis.org

2, 12, 602, 12840, 2387180, 99827160, 41521045376, 2751754706832, 2063225889204272, 194478305002268064, 232628053298868289568, 29191372156840204219200, 51464654047934299798487552
Offset: 1

Views

Author

R. H. Hardin, Sep 04 2012

Keywords

Comments

Column 5 of A216338.

Examples

			Some solutions for n=4
..0..x..1..x..2....0..x..1..x..2....0..x..1..x..2....0..x..1..x..0
..x..3..x..4..x....x..3..x..1..x....x..3..x..0..x....x..2..x..3..x
..1..x..5..x..3....2..x..0..x..3....1..x..4..x..5....4..x..1..x..0
..x..4..x..0..x....x..2..x..0..x....x..6..x..7..x....x..0..x..4..x
		

Crossrefs

Cf. A216338.

A216336 Number of horizontal and antidiagonal neighbor colorings of the even squares of an nX6 array with new integer colors introduced in row major order.

Original entry on oeis.org

2, 42, 2440, 373780, 87852160, 37060650272, 20358402201792, 17131843186425504, 17423570614012565376, 24860319276726031245440, 41082882676098706722895360, 90015726535715347904300537088, 222247072052822589353800809064448
Offset: 1

Views

Author

R. H. Hardin Sep 04 2012

Keywords

Comments

Column 6 of A216338

Examples

			Some solutions for n=4
..0..x..1..x..0..x....0..x..1..x..0..x....0..x..1..x..2..x....0..x..1..x..0..x
..x..2..x..3..x..1....x..2..x..3..x..4....x..0..x..3..x..4....x..2..x..3..x..2
..1..x..0..x..2..x....1..x..5..x..0..x....4..x..5..x..1..x....1..x..4..x..0..x
..x..3..x..4..x..3....x..4..x..5..x..2....x..6..x..3..x..2....x..0..x..2..x..0
		

A216337 Number of horizontal and antidiagonal neighbor colorings of the even squares of an nX7 array with new integer colors introduced in row major order.

Original entry on oeis.org

5, 136, 61915, 12297870, 33093354906, 18383343930862, 148049849072167133, 166176901557427161788, 2985013124775648539788601, 5737167226254078112766902750, 194564626464285317322710261641286
Offset: 1

Views

Author

R. H. Hardin Sep 04 2012

Keywords

Comments

Column 7 of A216338

Examples

			Some solutions for n=4
..0..x..1..x..2..x..3....0..x..1..x..2..x..0....0..x..1..x..2..x..3
..x..0..x..4..x..5..x....x..0..x..3..x..4..x....x..0..x..3..x..1..x
..1..x..0..x..1..x..6....1..x..0..x..1..x..0....1..x..2..x..3..x..1
..x..7..x..2..x..4..x....x..5..x..2..x..5..x....x..4..x..5..x..6..x
		

A216339 Number of horizontal and antidiagonal neighbor colorings of the even squares of a 3Xn array with new integer colors introduced in row major order.

Original entry on oeis.org

2, 3, 15, 42, 602, 2440, 61915, 322776, 12297978, 77360796, 4044784633, 29562890886, 2004648242718, 16604827619828, 1404640885455993, 12954736337254696, 1328741141974378250, 13465808369740333664
Offset: 1

Views

Author

R. H. Hardin Sep 04 2012

Keywords

Comments

Row 3 of A216338

Examples

			Some solutions for n=4
..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
..x..2..x..3....x..2..x..0....x..2..x..3....x..2..x..3....x..2..x..0
..4..x..2..x....3..x..2..x....0..x..1..x....4..x..1..x....1..x..2..x
		

A216340 Number of horizontal and antidiagonal neighbor colorings of the even squares of a 4Xn array with new integer colors introduced in row major order.

Original entry on oeis.org

2, 10, 52, 726, 12840, 373780, 12297870, 580853761, 29562890980, 2004648246554, 142953068558998, 12954739605661928, 1216988850964527370, 140585911310155419266, 16679506383419809650408, 2374936932537133281235971
Offset: 1

Views

Author

R. H. Hardin Sep 04 2012

Keywords

Comments

Row 4 of A216338

Examples

			Some solutions for n=4
..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
..x..2..x..3....x..2..x..3....x..2..x..3....x..0..x..1....x..2..x..3
..4..x..0..x....4..x..5..x....3..x..1..x....2..x..3..x....0..x..2..x
..x..5..x..3....x..3..x..0....x..3..x..1....x..2..x..1....x..0..x..4
		

A216331 Number of horizontal and antidiagonal neighbor colorings of the even squares of an n X n array with new integer colors introduced in row major order.

Original entry on oeis.org

1, 2, 15, 726, 2387180, 37060650272, 148049849072167133, 2765650089185458968363718
Offset: 1

Views

Author

R. H. Hardin Sep 04 2012

Keywords

Comments

Diagonal of A216338

Examples

			Some solutions for n=4
..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
..x..0..x..1....x..0..x..2....x..2..x..0....x..2..x..3....x..0..x..2
..2..x..3..x....2..x..0..x....1..x..2..x....3..x..2..x....3..x..4..x
..x..2..x..1....x..3..x..4....x..0..x..3....x..1..x..3....x..2..x..5
		

A216341 Number of horizontal and antidiagonal neighbor colorings of the even squares of a 5Xn array with new integer colors introduced in row major order.

Original entry on oeis.org

5, 27, 877, 15144, 2387180, 87852160, 33093354906, 2004646634218, 1404640885994156, 123560104158582188, 140585911310274456089
Offset: 1

Views

Author

R. H. Hardin Sep 04 2012

Keywords

Comments

Row 5 of A216338

Examples

			Some solutions for n=4
..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
..x..2..x..3....x..2..x..3....x..2..x..3....x..2..x..0....x..2..x..3
..3..x..4..x....1..x..4..x....1..x..4..x....1..x..3..x....4..x..1..x
..x..3..x..1....x..1..x..0....x..5..x..3....x..0..x..1....x..5..x..2
..4..x..2..x....2..x..1..x....4..x..2..x....3..x..2..x....2..x..4..x
		
Showing 1-10 of 12 results. Next