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.

A106210 Triangular matrix T, read by rows, that satisfies: [T^-1](n,k) = -k^2*T(n-2,k) when (n-2)>=k>=0, with T(n,n) = 1 and T(n+1,n) = (2*n+1) for n>=0.

Original entry on oeis.org

1, 1, 1, 3, 3, 1, 16, 16, 5, 1, 127, 127, 39, 7, 1, 1363, 1363, 416, 72, 9, 1, 18628, 18628, 5671, 967, 115, 11, 1, 311250, 311250, 94643, 16027, 1864, 168, 13, 1, 6173791, 6173791, 1876160, 316600, 36415, 3191, 231, 15, 1, 142190703, 142190703
Offset: 0

Views

Author

Paul D. Hanna, May 01 2005

Keywords

Comments

Both column 0 and column 1 form A082161. Row sums form A106211.

Examples

			Triangle T begins:
1;
1,1;
3,3,1;
16,16,5,1;
127,127,39,7,1;
1363,1363,416,72,9,1;
18628,18628,5671,967,115,11,1;
311250,311250,94643,16027,1864,168,13,1;
6173791,6173791,1876160,316600,36415,3191,231,15,1; ...
Matrix inverse T^-1 begins:
1;
-1,1;
0,-3,1;
0,-1,-5,1;
0,-3,-4,-7,1;
0,-16,-20,-9,-9,1;
0,-127,-156,-63,-16,-11,1;
0,-1363,-1664,-648,-144,-25,-13,1;
0,-18628,-22684,-8703,-1840,-275,-36,-15,1; ...
where [T^-1](n,k) = -k^2*T(n-2,k) when (n-2)>=k>=0.
G.f. for column 0: 1/(1-0x) = 1*(1-1x) + 1*x*(1-1x)(1-2x) +
3*x^2*(1-1x)(1-2x)(1-3x) + 16*x^3*(1-1x)(1-2x)(1-3x)(1-4x) + ...
+ T(n,0)*x^n*(1-1x)(1-2x)*..*(1-(n+1)*x) + ...
G.f. for column 1: 1/(1-1x) = 1*(1-2x) + 3*x*(1-2x)(1-3x) +
16*x^2*(1-2x)(1-3x)(1-4x) + 127*x^3*(1-2x)(1-3x)(1-4x)(1-5x) + ...
+ T(n+1,1)*x^n*(1-2x)(1-3x)*..*(1-(n+2)*x) + ...
G.f. for column 2: 1/(1-2x) = 1*(1-3x) + 5*x*(1-3x)(1-4x) +
39*x^2*(1-3x)(1-4x)(1-5x) + 416*x^3*(1-3x)(1-4x)(1-5x)(1-6x) + ...
+ T(n+2,2)*x^n*(1-3x)(1-4x)*..*(1-(n+3)*x) + ...
		

Crossrefs

Programs

  • PARI
    T(n,k)=if(n
    				
  • PARI
    T(n,k)=local(A=matrix(1,1),B);A[1,1]=1; for(m=2,n+2,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=j,if(j==1,B[i,j]=(A^2)[i-1,1], B[i,j]=(A^2)[i-1,j]));));A=B); return(if(k==0,if(n==0,1,A[n+1,k+1]),A[n+1,k]/k^2))

Formula

T(n, k) = A102086(n, k)/(k+1) for n>=0, k>=0. T(n, 0) = A082161(n) for n>0, with T(0, 0) = 1. G.f. for column k: 1/(1-k*x) = Sum_{n>=0} T(n+k, k)*x^n*prod_{j=1, n+1} (1-(j+k)*x).