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.

A058390 Number of 4 X 4 matrices with nonnegative integer entries and all row sums equal to n, up to row and column permutation.

Original entry on oeis.org

1, 5, 53, 458, 3411, 19865, 95214, 383714, 1346183, 4202086, 11905966, 31061806, 75533056, 172800689, 374861365, 775978710, 1541027694, 2949003213, 5458806804, 9805626744, 17140511056
Offset: 0

Views

Author

Vladeta Jovovic, Nov 24 2000

Keywords

Crossrefs

Programs

A052282 Number of 3 X 3 stochastic matrices under row and column permutations.

Original entry on oeis.org

1, 1, 3, 5, 9, 13, 22, 30, 45, 61, 85, 111, 149, 189, 244, 304, 381, 465, 571, 685, 825, 977, 1158, 1354, 1585, 1833, 2121, 2431, 2785, 3165, 3596, 4056, 4573, 5125, 5739, 6393, 7117, 7885, 8730, 9626, 10605, 11641, 12769, 13959, 15249, 16609, 18076, 19620
Offset: 0

Views

Author

Vladeta Jovovic, Feb 06 2000

Keywords

Comments

Unreduced numerators in convergent to log(2) = lim[n->inf, a(n)/A000670(n+1)].

Examples

			There are 5 nonisomorphic 3 X 3 matrices with row and column sums 3:
[0 0 3] [0 0 3] [0 1 2] [0 1 2] [1 1 1]
[0 3 0] [1 2 0] [1 1 1] [1 2 0] [1 1 1]
[3 0 0] [2 1 0] [2 1 0] [2 0 1] [1 1 1]
		

Crossrefs

Row n=3 of A333733.
Cf. A002817, A052280, A052281. Different from A001993.

Programs

  • Maple
    a:= n -> (Matrix([[1, 0, 0, 1, 1, 3, 5, 9, 13]]). Matrix(9, (i,j)-> if (i=j-1) then 1 elif j=1 then [2, 1, -3, -1, 1, 3, -1, -2, 1][i] else 0 fi)^n)[1,1]: seq(a(n), n=0..50);  # Alois P. Heinz, Jul 31 2008
  • Mathematica
    LinearRecurrence[{2,1,-3,-1,1,3,-1,-2,1},{1,1,3,5,9,13,22,30,45},50] (* Harvey P. Dale, Mar 10 2018 *)

Formula

G.f.: (x^6-x^5+x^3-x+1)/((1-x)^5*(1+x)^2*(1+x+x^2)). - Ralf Stephan and Vladeta Jovovic, May 07 2004

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

Views

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
Showing 1-3 of 3 results.