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.

A106338 Triangle T, read by rows, equal to the matrix inverse of the triangle defined by [T^-1](n,k) = A075263(n,k)/n!, for n>=k>=0.

Original entry on oeis.org

1, 1, -1, 1, -3, 2, 1, -9, 14, -6, 1, -45, 110, -90, 24, 1, -585, 1670, -1710, 744, -120, 1, -21105, 61670, -66150, 32424, -7560, 720, 1, -1858185, 5439350, -5864670, 2925384, -728280, 91440, -5040, 1, -367958745, 1077215510, -1161894510, 580489224, -145567800, 18961200, -1285200, 40320, 1
Offset: 0

Views

Author

Paul D. Hanna, May 01 2005

Keywords

Comments

Row sums are zero after the initial row. Absolute row sums equal A106339.

Examples

			Triangle begins:
1;
1,-1;
1,-3,2;
1,-9,14,-6;
1,-45,110,-90,24;
1,-585,1670,-1710,744,-120;
1,-21105,61670,-66150,32424,-7560,720;
1,-1858185,5439350,-5864670,2925384,-728280,91440,-5040; ...
The matrix inverse T^-1 begins:
1;
1,1;
1,3/2,1/2;
1,2,7/6,1/6;
1,5/2,25/12,5/8,1/24;
1,3,13/4,3/2,31/120,1/120;
1,7/2,14/3,35/12,301/360,7/80,1/720; ...
where [T^-1](n,k) = A075263(n,k)/n!.
Each row n of the matrix inverse equals the initial
(n+1) fractional coefficients of (x/log(1+x))^n,
which are listed below for n=1,2,3,...,9:
1; 1/2,-1/12,1/24,-19/720,3/160,-863/60480,275/24192,...
1,1; 1/12,0,-1/240,1/240,-221/60480,19/6048,...
1,3/2,1/2; 0,1/240,-1/480,1/945,-11/20160,47/172800,...
1,2,7/6,1/6; -1/720,0,1/3024,-1/3024,199/725760,...
1,5/2,25/12,5/8,1/24; 0,-1/6048,1/12096,-19/725760,...
1,3,13/4,3/2,31/120,1/120; 1/30240,0,-1/57600,1/57600,...
1,7/2,14/3,35/12,301/360,7/80,1/720; 0,1/172800,...
1,4,19/3,5,81/40,23/60,127/5040,1/5040; -1/1209600,0,...
1,9/2,33/4,63/8,331/80,37/32,605/4032,17/2688,1/40320; 0,...
		

Crossrefs

Programs

  • Mathematica
    rows = 10; Tinv = Table[(1/n!)*PadRight[CoefficientList[x^(n+1)*Sum[k^n * (1-x)^k, {k, 0, Infinity}], x], rows], {n, 0, rows-1}]; T = Inverse[Tinv ]; Table[T[[n, k]], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Sep 11 2017 *)
  • PARI
    T(n,k)=(M=matrix(n+1,n+1,m,j,if(m>=j, polcoeff((-x/log(1-x+x^2*O(x^n)))^m,j-1)))^-1)[n+1,k+1]
    
  • PARI
    T(n,k)=(-1)^n*k!*(matrix(n+1,n+1,r,c,if(r>=c,(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

Also, T(n, k) = k!*A106340(n, k), where A106340 is the matrix inverse of the triangle formed from (n-k)!*A008278(n, k), n>=k>=0 and A008278 is the triangle of Stirling numbers of 2nd kind.