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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A141681 The matrix inverse of the triangle A141680.

Original entry on oeis.org

1, -4, 1, -9, 0, 1, 32, -12, 0, 1, -25, 0, 0, 0, 1, 504, -45, -40, 0, 0, 1, -49, 0, 0, 0, 0, 0, 1, -4096, 1568, 0, -140, 0, 0, 0, 1, 2187, 0, -252, 0, 0, 0, 0, 0, 1, 13400, -225, 0, 0, -504, 0, 0, 0, 0, 1, -121, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 1

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Author

Roger L. Bagula and Gary W. Adamson, Sep 07 2008

Keywords

Comments

Row sums are 1, -3, -8, 21, -24, 420, -48, -2667, 1936, 12672, ...

Examples

			Triangle begins
      1;
     -4,    1;
     -9,    0,    1;
     32,  -12,    0,    1;
    -25,    0,    0,    0,    1;
    504,  -45,  -40,    0,    0,    1;
    -49,    0,    0,    0,    0,    0,    1;
  -4096, 1568,    0, -140,    0,    0,    0,    1;
   2187,    0, -252,    0,    0,    0,    0,    0,    1;
  13400, -225,    0,    0, -504,    0,    0,    0,    0,    1;
		

Crossrefs

Cf. A126988.

Programs

  • Mathematica
    t[n_, m_] = If[Mod[n, m] == 0, n/m, 0]*Binomial[n, m]; Table[Table[t[n, m], {m, 1, n}], {n, 1, 10}]; Flatten[%]; Table[Sum[t[n, m], {m, 1, n}], {n, 1, 10}]; M = Inverse[Table[Table[t[n, m], {m, 1, 10}], {n, 1, 10}]]; Table[Table[M[[n, m]], {m, 1, n}], {n, 1, 10}]; Flatten[%]

Formula

Sum_{j=k..n} T(n,j) * A141680(j,k) = delta(n,k).
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