Student Number Theory seminar

Monday, June 3, 2013 11:30 pm - 11:30 pm EDT (GMT -04:00)

J C Saunders, Pure Mathematics Department, University of Waterloo

“Sums of Digits in q-ary expansions”

Let sq(n) denote the sum of the digits of a number n in base q. For example, s2(n) represents the number of 1s in the binary expansion of n. In 1978, Kenneth B. Stolarsky showed that
lim inf s2(n2) = 0 n→∞ s2(n)
using bounds obtained from analytical methods. In this presentation, we verify the above using algebraic methods to show that we can find an n such that the ratio
s2(n2)
s2 (n) is any given positive rational number. We will also see that a few other intersting results about the
analogous ratio involving other bases and other powers, including fractional exponents.