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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A067209 Number of n X n 0..1 matrices with all row and column sums equal.

Original entry on oeis.org

1, 2, 4, 14, 140, 4322, 434542, 144109562, 165431317452, 654143160457922, 9331115832294448754, 469229841129645179004962, 87481268294773501231007850158, 58328998963405322376273800187396962, 147013017541698957281403494604070439260442
Offset: 0

Views

Author

R. H. Hardin, Feb 20 2002

Keywords

Examples

			Some solutions for n=5
..1..1..0..0..1....0..0..1..0..1....0..1..0..1..1....1..1..0..1..0
..1..1..0..0..1....1..1..0..0..0....1..1..0..0..1....1..0..1..1..0
..0..0..1..1..1....1..0..0..1..0....1..1..1..0..0....1..0..1..0..1
..1..0..1..1..0....0..1..1..0..0....0..0..1..1..1....0..1..0..1..1
..0..1..1..1..0....0..0..0..1..1....1..0..1..1..0....0..1..1..0..1
		

Crossrefs

Row sums of A008300.
Column k=1 of A202784.

Extensions

Added one term and example - R. H. Hardin, Jan 05 2012
a(0)=1 prepended and more terms (using data provided by B. D. McKay) from Alois P. Heinz, Apr 12 2017

A058527 Number of 2n X 2n 0-1 matrices with n ones in each row and each column.

Original entry on oeis.org

1, 2, 90, 297200, 116963796250, 6736218287430460752, 64051375889927380035549804336, 108738182111446498614705217754614976371200, 34812290428176298285394893936773707951192224124239796250, 2188263032066768922535710968724036448759525154977348944382853301460850000
Offset: 0

Views

Author

David desJardins, Dec 22 2000

Keywords

Crossrefs

Central coefficients of A008300.
Main diagonal of A376935.

Extensions

More terms (using dynamic programming in Python) from Greg Kuperberg, Feb 08 2001
More terms from Vladeta Jovovic, Nov 12 2006

A075754 Number of n X n (0,1) matrices containing exactly five 1's in each row and in each column.

Original entry on oeis.org

1, 720, 3110940, 24046189440, 315031400802720, 6736218287430460752, 226885231700215713535680, 11649337108041078980732943360, 885282776210120715086715619724160, 96986285294151066094112970262797953280
Offset: 5

Views

Author

Michel Buffet (buffet(AT)engref.fr), Oct 08 2002

Keywords

Comments

Also number of ways to arrange 5n rooks on an n X n chessboard, with no more than 5 rooks in each row and column. - Vaclav Kotesovec, Aug 04 2013
Generally (Canfield + McKay, 2004), a(n) ~ exp(-1/2)*binomial(n,s)^(2*n) / binomial(n^2,s*n), or a(n) ~ sqrt(2*Pi)*exp(-n*s-1/2*(s-1)^2)*(n*s)^(n*s+1/2)*(s!)^(-2*n). - Vaclav Kotesovec, Aug 04 2013

References

  • B. D. McKay, Applications of a technique for labeled enumeration, Congressus Numerantium, 40 (1983) 207-221.

Crossrefs

Column 5 of A008300.

Formula

From Vaclav Kotesovec, Aug 04 2013: (Start)
a(n) ~ exp(-1/2)*binomial(n,5)^(2*n) / binomial(n^2,5*n), (Canfield + McKay, 2004)
a(n) ~ sqrt(Pi)*2^(1/2-6*n)*5^(3*n+1/2) *9^(-n)*exp(-5*n-8)*n^(5*n+1/2)
(End)

Extensions

More terms from Brendan McKay, Jan 08 2005

A283500 Triangle read by rows: T(n,k) = number of n X n (0,1) matrices with at most k 1's in each row or column.

Original entry on oeis.org

2, 7, 16, 34, 265, 512, 209, 7343, 41503, 65536, 1546, 304186, 6474726, 24997921, 33554432, 13327, 17525812, 1709852332, 21252557377, 57366997447, 68719476736, 130922, 1336221251, 702998475376, 34215495252681, 252540841305558, 505874809287625
Offset: 1

Views

Author

R. J. Mathar, Mar 09 2017

Keywords

Examples

			Triangle begins:
2;
7,     16;
34,    265,      512;
209,   7343,     41503,      65536;
1546,  304186,   6474726,    24997921,    33554432;
13327, 17525812, 1709852332, 21252557377, 57366997447, 68719476736;
...
		

Crossrefs

Cf. A002720 (column k=1), A197458 (column k=2), A008300 (exactly k 1s).
Main diagonal and first lower diagonal give: A002416, A048291.
Cf. A247158 (k=n/2).

A172541 Number of n X n 0..1 arrays with row sums 7 and column sums 7.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 40320, 14398171200, 8302816499443200, 7722015017013984456000, 11649337108041078980732943360, 28278447454165011203551734584421120, 108738182111446498614705217754614976371200
Offset: 1

Views

Author

R. H. Hardin, Feb 06 2010

Keywords

Crossrefs

Column 7 of A008300, Cf. A075754.

A172544 Number of n X n 0..1 arrays with row sums 6 and column sums 6.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 5040, 187530840, 12025780892160, 1289144584143523800, 226885231700215713535680, 64051375889927380035549804336, 28278447454165011203551734584421120
Offset: 1

Views

Author

R. H. Hardin Feb 06 2010

Keywords

Comments

Also number of ways to arrange 6n rooks on an n X n chessboard, with no more than 6 rooks in each row and column. - Vaclav Kotesovec, Aug 04 2013
Generally (Canfield + McKay, 2004), a(n) ~ exp(-1/2)*binomial(n,s)^(2*n) / binomial(n^2,s*n), or a(n) ~ sqrt(2*Pi)*exp(-n*s-1/2*(s-1)^2)*(n*s)^(n*s+1/2)*(s!)^(-2*n). - Vaclav Kotesovec, Aug 04 2013

Crossrefs

Column 6 of A008300.

Formula

From Vaclav Kotesovec, Aug 04 2013: (Start)
a(n) ~ exp(-1/2)*binomial(n,6)^(2*n)/binomial(n^2,6*n), (Canfield + McKay, 2004)
a(n) ~ sqrt(Pi)*2^(1-2*n)*3^(2*n+1/2)*5^(-2*n)*exp(-6*n-25/2)*n^(6*n+1/2)
(End)

A172534 Number of n X n 0..1 arrays with row sums 12 and column sums 12.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6227020800, 676508133623135814000, 65662040698002721810659005184000, 6892692735539278753058456514221737762215000
Offset: 1

Views

Author

R. H. Hardin, Feb 06 2010

Keywords

Crossrefs

Column k=12 of A008300.

A172535 Number of n X n 0..1 arrays with row sums 11 and column sums 11.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 479001600, 3574340599104475200, 27537152449960680597739468800, 254143667822686635850590661555095468000, 3183529624645847695375078143769686741065620316160
Offset: 1

Views

Author

R. H. Hardin, Feb 06 2010

Keywords

Crossrefs

Column k=11 of A008300.

A172536 Number of n X n 0..1 arrays with row sums 8 and column sums 8.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 362880, 1371785398200, 7673688777463632000, 65599839591251908982712750, 885282776210120715086715619724160, 19040419266278799766631032461849139013040
Offset: 1

Views

Author

R. H. Hardin, Feb 06 2010

Keywords

Crossrefs

Column k=8 of A008300.

A172537 Number of n X n 0..1 arrays with row sums 14 and column sums 14.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1307674368000, 36574751938491748341360000, 665825560532772251175492202972938240000, 10431401634793817906193873163767479249710797568200000
Offset: 1

Views

Author

R. H. Hardin, Feb 06 2010

Keywords

Crossrefs

Column k=14 of A008300.
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