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 11-19 of 19 results.

A005467 6 X 6 stochastic matrices of integers.

Original entry on oeis.org

1, 714, 196677, 18941310, 809451144, 17914693608, 223688514048, 1633645276848, 6907466271384, 15642484909560, 14666561365176
Offset: 0

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Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • M. L. Stein and P. R. Stein, Enumeration of Stochastic Matrices with Integer Elements. Report LA-4434, Los Alamos Scientific Laboratory of the University of California, Los Alamos, NM, Jun 1970.

Crossrefs

Cf. A005466.

Extensions

a(10) corrected by Andrew Howroyd, Apr 09 2020

A052280 Number of 4 X 4 stochastic matrices under row and column permutations.

Original entry on oeis.org

1, 1, 5, 12, 43, 106, 321, 787, 1960, 4354, 9386, 18790, 36362, 66789, 118936, 203840, 340195, 551192, 873343, 1351457, 2052221, 3056798, 4480565, 6462678, 9194098, 12902867, 17892986, 24524478, 33265476, 44666016, 59426834, 78364873, 102502765, 133024660, 171390035, 219278224
Offset: 0

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Author

Vladeta Jovovic, Feb 06 2000

Keywords

Examples

			There are 5 nonisomorphic 4 X 4 matrices with row and column sums 2:
[0 0 0 2] [0 0 0 2] [0 0 0 2] [0 0 1 1] [0 0 1 1]
[0 0 2 0] [0 0 2 0] [0 1 1 0] [0 0 1 1] [0 1 0 1]
[0 2 0 0] [1 1 0 0] [1 0 1 0] [1 1 0 0] [1 0 1 0]
[2 0 0 0] [1 1 0 0] [1 1 0 0] [1 1 0 0] [1 1 0 0]
		

Crossrefs

Row n=4 of A333733.

Extensions

Terms a(9) and beyond from Andrew Howroyd, Apr 04 2020

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

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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

A172862 Number of n X n 0..5 arrays with row sums 5 and column sums 5.

Original entry on oeis.org

1, 1, 6, 231, 40176, 22069251, 30767936616, 94161778046406, 569304690994400256, 6274236760589024662176, 118285830126660123474844752, 3623440212198461411381072575512, 172850452498398420310370097345242112
Offset: 0

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Author

R. H. Hardin, Feb 06 2010

Keywords

Crossrefs

Column k=5 of A257493.

A003439 Number of 6 X 6 stochastic matrices of integers: all rows and columns sum to n.

Original entry on oeis.org

1, 720, 202410, 20933840, 1047649905, 30767936616, 602351808741, 8575979362560, 94459713879600, 842286559093240, 6292583664553881, 40447642842118656, 228438173705550566, 1152877640765297760, 5271278793334883190, 22085628572718605376, 85604721304213863531
Offset: 0

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Author

Keywords

References

  • Matthias Beck and Dennis Pixton, The Ehrhart Polynomial of the Birkhoff Polytope, Discrete & Computational Geometry, 30(4)(2003), 623-637.
  • D. M. Jackson and G. H. J. van Rees, The enumeration of generalized double stochastic nonnegative integer square matrices, SIAM J. Comput., 4 (1975), 474-477.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Row n=6 of A257493.
Cf. A005467.

Formula

a(n) = Sum_{j=0..10} A005467(j) * binomial(5+j+n, 5+2*j). - Andrew Howroyd, Apr 09 2020

Extensions

More terms from Melissa Erdmann (merdmann(AT)nebrwesleyan.edu), May 07 2009
Offset changed to 0 by Alois P. Heinz, Apr 26 2015
Name clarified by Charles R Greathouse IV, Mar 03 2018

A005466 5 X 5 stochastic matrices of integers.

Original entry on oeis.org

1, 115, 5390, 101275, 858650, 3309025, 4718075
Offset: 0

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Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • M. L. Stein and P. R. Stein, Enumeration of Stochastic Matrices with Integer Elements. Report LA-4434, Los Alamos Scientific Laboratory of the University of California, Los Alamos, NM, Jun 1970.

Crossrefs

A052281 Number of 4 X 4 symmetric stochastic matrices under row and column permutations.

Original entry on oeis.org

1, 1, 3, 6, 16, 29, 62, 107, 195, 320, 522, 804, 1234, 1804, 2626, 3700, 5155, 7038
Offset: 0

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Author

Vladeta Jovovic, Feb 06 2000

Keywords

Comments

This sequence appears to be an erroneous version of A333886.

Examples

			There are 6 nonisomorphic symmetric 4 X 4 matrices with row and column sums 3:
[0 0 0 3] [0 0 1 2] [0 0 1 2] [0 0 1 2] [0 0 1 2] [0 1 1 1]
[0 0 3 0] [0 0 2 1] [0 1 1 1] [0 1 2 0] [0 2 1 0] [1 0 1 1]
[0 3 0 0] [1 2 0 0] [1 1 1 0] [1 2 0 0] [1 1 0 1] [1 1 0 1]
[3 0 0 0] [2 1 0 0] [2 1 0 0] [2 0 0 1] [2 0 1 0] [1 1 1 0]
But, A333886 gives 6 other cases.
		

Crossrefs

A172806 Number of n X n of nonnegative integers with all row and column sums equal to 4.

Original entry on oeis.org

1, 1, 5, 120, 10147, 2224955, 1047649905, 936670590450, 1455918295922650, 3680232136895819610, 14356628851597700179050, 82857993930808028192521800, 683327637694741065563262206250, 7821620120684573354895941635688250
Offset: 0

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Author

R. H. Hardin, Feb 06 2010

Keywords

Crossrefs

A123228 Sum of the n-th powers of the roots of the polynomial x^6 + 14x^5 + 87x^4 + 148x^3 + 87x^2 + 14x + 1.

Original entry on oeis.org

6, -14, 22, 466, -6714, 51346, -205418, -638414, 19787526, -195455054, 1126500502, -1636604654, -47878102074, 662684162386, -4965254864618, 19072814136946, 71067700116486, -1976406503675534, 19086772122105622, -107375947452919214, 128777308208472006, 4884916184617735186
Offset: 0

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Author

N. J. A. Sloane, Nov 12 2006

Keywords

Crossrefs

This polynomial arises in A001496. Cf. A123259.

Programs

  • Maple
    Newt:=proc(f) local t1,t2,t3,t4; t1:=f; t2:=diff(f,x); t3:=expand(x^degree(t1,x)*subs(x=1/x,t1)); t4:=expand(x^degree(t2,x)*subs(x=1/x,t2)); factor(t4/t3); end;
    t1:=1+14*x+87*x^2+148*x^3+87*x^4+14*x^5+x^6; Newt(t1); series(t1,x,50);
  • PARI
    polsym(x^6 + 14*x^5 + 87*x^4 + 148*x^3 + 87*x^2 + 14*x + 1, 30) \\ Charles R Greathouse IV, Jul 20 2016

Formula

G.f.: 2*(7*x^4+80*x^3+142*x^2+32*x+3)/((x+1)*(x^4+12*x^3+62*x^2+12*x+1)).
Previous Showing 11-19 of 19 results.