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.

A111978 Matrix log of triangle A111975, which shifts columns left and up under matrix square; these terms are the result of multiplying each element in row n and column k by (n-k)!.

Original entry on oeis.org

0, 1, 0, 0, 2, 0, 16, 0, 4, 0, 0, 32, 0, 8, 0, 1536, 0, 64, 0, 16, 0, 0, 3072, 0, 128, 0, 32, 0, -319488, 0, 6144, 0, 256, 0, 64, 0, 0, -638976, 0, 12288, 0, 512, 0, 128, 0, 36007575552, 0, -1277952, 0, 24576, 0, 1024, 0, 256, 0, 0, 72015151104, 0, -2555904, 0, 49152, 0, 2048, 0, 512, 0
Offset: 0

Views

Author

Paul D. Hanna, Aug 25 2005

Keywords

Comments

Column k equals 2^k multiplied by column 0 (A111979) when ignoring zeros above the diagonal.

Examples

			Matrix log of A111975, with factorial denominators, begins:
0;
1/1!, 0;
0/2!, 2/1!, 0;
16/3!, 0/2!, 4/1!, 0;
0/4!, 32/3!, 0/2!, 8/1!, 0;
1536/5!, 0/4!, 64/3!, 0/2!, 16/1!, 0;
0/6!, 3072/5!, 0/4!, 128/3!, 0/2!, 32/1!, 0;
-319488/7!, 0/6!, 6144/5!, 0/4!, 256/3!, 0/2!, 64/1!, 0; ...
		

Crossrefs

Cf. A111975 (triangle), A111979 (column 0).

Programs

  • PARI
    T(n,k,q=2)=local(A=Mat(1),B);if(n2,(A^q)[i-1,2],1), B[i,j]=(A^q)[i-1,j-1]));));A=B); B=sum(i=1,#A,-(A^0-A)^i/i);return((n-k)!*B[n+1,k+1]))

Formula

T(n, k) = 2^k*T(n-k, 0) = 2^k*A111979(n-k) for n>=k>=0.