Observations on power series involving logarithmic singularities

[jaydfox]

However this is not the matrix operator method of Gottfried...

I was pretty sure it wasn't, though the use of the same matrices implies a fundamental connection. But after reading his posts and seeing the similarities, it opened my eyes to the fact that the Vandermonde matrix was effectively a factorial scaled set of coefficients for powers of the power series for exp, and I had already figured out how to compose series a couple weeks ago by using powers of power series, so a lightbulb went off. So even though the methods may be different, I still have Gottfried to thank for explaining things in a way that helped me to see this.