Number Theory seminar

Thursday, November 7, 2013 1:30 pm - 1:30 pm EST (GMT -05:00)

John J.C. Saunders, Department of Pure Mathematics, University of Waterloo

“Sums of Digits in q-ary expansions”

Let sq(n) denote the sum of the digits of a number n expressed in base q. We study here the ratio sq(nα)

sq (n)
for various values of
q and α. In 1978, Kenneth B. Stolarsky showed that

and that

lim inf s2(n2) = 0 n→∞ s2(n)

lim sup s2(n2) = n→∞ s2(n)

using an explicit construction. We show that for α = 2 and q 2, the above ratio can in fact be any positive rational number. If time permits, we also study what happens when α is a rational number that is not an integer, terminating the resulting expression by using the floor function.