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.

A106342 Matrix inverse of A008278, which is the reflected triangle of the Stirling numbers of 2nd kind.

Original entry on oeis.org

1, -1, 1, 2, -3, 1, -9, 15, -7, 1, 94, -160, 80, -15, 1, -2220, 3790, -1915, 375, -31, 1, 114456, -195461, 98875, -19460, 1652, -63, 1, -12542341, 21419587, -10836231, 2133635, -181559, 7035, -127, 1, 2868686486, -4899099640, 2478483560, -488022556, 41534164, -1611120, 29360, -255, 1
Offset: 0

Views

Author

Paul D. Hanna, May 01 2005

Keywords

Examples

			Triangle T begins:
          1;
         -1,        1;
          2,       -3,         1;
         -9,       15,        -7,       1;
         94,     -160,        80,     -15,       1;
      -2220,     3790,     -1915,     375,     -31,    1;
     114456,  -195461,     98875,  -19460,    1652,  -63,    1;
  -12542341, 21419587, -10836231, 2133635, -181559, 7035, -127, 1;
		

Crossrefs

Row sums are A000007.
Column 0 is A106343.

Programs

  • PARI
    {T(n,k)=(matrix(n+1,n+1,r,c,if(r>=c, sum(m=0,r-c+1,(-1)^(r-c+1-m)*m^r/m!/(r-c+1-m)!)))^-1)[n+1,k+1]}

Formula

T(n, k) = (Stirling2(n, n-k))^[-1], where T^[-1] denotes the matrix inverse of T.