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 1-3 of 3 results.

A003438 Number of 5 X 5 matrices with nonnegative integer entries and row and column sums equal to n.

Original entry on oeis.org

1, 120, 6210, 153040, 2224955, 22069251, 164176640, 976395820, 4855258305, 20856798285, 79315936751, 272095118010, 854560160105, 2486299719645, 6765755480415, 17356306529251, 42250330784180, 98137852369965
Offset: 0

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Author

Keywords

Comments

Number of 5 X 5 stochastic matrices of integers.

References

  • 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).
  • R. P. Stanley, Enumerative Combinatorics, Wadsworth, Vol. 1, 1986, p. 234.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(1+103x+4306x^2+63110x^3+388615x^4+1115068x^5+ 1575669x^6+1115068x^7+388615x^8+63110x^9+4306x^10+103x^11+x^12)/ (1-x)^17,{x,0,30}],x] (* Harvey P. Dale, Aug 17 2013 *)

Formula

G.f.: (1 + 103*x + 4306*x^2 + 63110*x^3 + 388615*x^4 + 1115068*x^5 + 1575669*x^6 + 1115068*x^7 + 388615*x^8 + 63110*x^9 + 4306*x^10 + 103*x^11 + x^12)/(1-x)^17.
a(n) = Sum_{j=0..6} A005466(j) * binomial(4+j+n, 4+2*j). - Andrew Howroyd, Apr 09 2020

Extensions

More terms from Vladeta Jovovic, Feb 06 2000

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

A259473 Irregular triangle read by rows of coefficients arising in the enumeration of doubly stochastic matrices of integers, n >= 1, 0 <= k <= (n-1)*(n-2).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 14, 87, 148, 87, 14, 1, 1, 103, 4306, 63110, 388615, 1115068, 1575669, 1115068, 388615, 63110, 4306, 103, 1, 1, 694, 184015, 15902580, 567296265, 9816969306, 91422589980, 490333468494, 1583419977390, 3166404385990, 3982599815746, 3166404385990
Offset: 1

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Author

N. J. A. Sloane, Jul 03 2015

Keywords

Comments

The n-th row of A257493 is a polynomial of degree (n-1)^2. This triangle gives the coefficients of the numerator of the generating functions for A257493 with denominators being (1-x)^(1+(n-1)^2). - Andrew Howroyd, Apr 11 2020

Examples

			Triangle begins:
  1;
  1;
  1,1,1;
  1,14,87,148,87,14,1;
  1,103,4306,63110,388615,1115068,1575669,1115068,388615,63110,4306,103,1;
  ...
		

Crossrefs

Row sums are A037302.

Formula

T(n,k) = Sum_{i=0..k} A257493(n, k-i)*(-1)^i*binomial(1+(n-1)^2,i). - Andrew Howroyd, Apr 11 2020

Extensions

a(1)=1 prepended and terms a(26) and beyond from Andrew Howroyd, Apr 11 2020
Showing 1-3 of 3 results.