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 1-2 of 2 results.

A204446 Permanent of the n-th principal submatrix of A204445.

Original entry on oeis.org

1, 1, 3, 9, 34, 116, 792, 4752, 32304, 202320, 1991952, 17927568, 175473216, 1613364480, 20695108608, 248341303296, 3173837230080, 38575603814400, 610011772416000, 9150176586240000, 144343174487040000, 2183607168215040000
Offset: 1

Views

Author

Clark Kimberling, Jan 15 2012

Keywords

Crossrefs

Programs

  • Mathematica
    f[i_, j_] :=
    Floor[(i + j + 4)/4] - Floor[(i + j + 1)/4];
    m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}]
    TableForm[m[8]] (* 8x8 principal submatrix *)
    Flatten[Table[f[i, n + 1 - i],
      {n, 1, 14}, {i, 1, n}]]    (* A204445 *)
    Permanent[m_] :=
      With[{a = Array[x, Length[m]]},
       Coefficient[Times @@ (m.a), Times @@ a]];
    Table[Permanent[m[n]], {n, 1, 22}] (* A204446 *)

A204244 Symmetric matrix given by f(i,1)=1, f(1,j)=1, f(i,i)=i! and f(i,j)=0 otherwise.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 0, 0, 1, 1, 0, 6, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 24, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 120, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 720, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 5040, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0
Offset: 1

Views

Author

Clark Kimberling, Jan 13 2012

Keywords

Examples

			Northwest corner:
1 1 1 1
1 2 0 0
1 0 6 0
1 0 0 24
		

Crossrefs

Programs

  • Mathematica
    f[i_, j_] := 0; f[1, j_] := 1; f[i_, 1] := 1; f[i_, i_] := i!;
    m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}]
    TableForm[m[8]] (* 8x8 principal submatrix *)
    Flatten[Table[f[i, n + 1 - i],
      {n, 1, 12}, {i, 1, n}]]      (* A204244 *)
    Table[Det[m[n]], {n, 1, 15}]   (* A204245 *)
    Permanent[m_] :=
      With[{a = Array[x, Length[m]]},
       Coefficient[Times @@ (m.a), Times @@ a]];
    Table[Permanent[m[n]], {n, 1, 14}]   (*  A203228 *)
Showing 1-2 of 2 results.