Toeplitz

[Michael Somos]

Wouter,
     In deed, you have found one of many such nice results. Actually,
The matrix you used is a "Hankel" matrix. The Toeplitz "leans the other
way". In this particular case, what you are seeing is that the general
result is the char poly is monic. The first coefficient after that is
the trace, which happens to be the sum of the even integers, namely,
the oblong numbers. The next coefficient is the sum of all the 2x2
minors, and is what you discovered it to be. After that, the higher
minors are all zero, hence this agrees also with what you found. Shalom,
Michael

-- 
Michael Somos <somos at grail.cba.csuohio.edu>     Cleveland State University
http://grail.cba.csuohio.edu/~somos/            Cleveland, Ohio, USA 44115