Volume 22
, Issue 3


I propose to describe how computer science depends heavily on mathematics, and how mathematics has been revolutionised by the advent of the computer.

We start with the sieve of Eratosthenes for generating primes, and then look at other ways of sieving the integers.

Ramanujan was an Indian and a very original mathematician.

The diagram on page 24 features a cross-section of the shell of a Pearly Nautilus, showing a remarkable example of a curve known as the equiangular, or logarithmic, spiral.

In this issue we first look at two problems, set in 1985, which use mathematical induction.

Q.684 $B\hat{A}C$ is an obtuse angle. A circle through $A$ cuts $AB$ at $P$ and $AC$ at $Q$.

Q.660 A jailer walks $n$ times past a row of $n$ cells walking always from left to right.