Do you know of any on-line references regarding relationships among the elementary number-theoretic functions?


The sort of thing I'm interested in is as at the Wikipedia page on [Arithmetic Functions](http://en.wikipedia.org/wiki/Arithmetic_function#Relations_among_the_functions).


Are there any others?


Thanks.



References for Relationships amongst the Number-theoretic Functions
There [some](http://www.math.ucla.edu/~cbm/aands/page_826.htm) in Abramowitz-Stegun, [Handbook of Mathematical Functions](http://www.math.ucla.edu/~cbm/aands/).


