In which years does February have five Sundays? How many right-angled triangles with whole-number sides have a side of length 29? How many shuffles are needed to restore the order of the cards in a pack with two Jokers? Are any of the numbers 11, 111, 1111, 11111, . . . perfect squares? Can one construct a regular polygon with 100 sides if measuring is forbidden? How do prime numbers help to keep our credit cards secure?

These are all questions in number theory, the branch of mathematics that’s primarily concerned with our counting numbers, 1, 2, 3, etc. Of particular importance are the prime numbers, the ‘building blocks’ of our number system.

The subject is an old one, dating back to the ancient Greeks, and for many years has been studied for its intrinsic beauty and elegance, not least because several of its challenges are so easy to state that everyone can understand them, and yet no-one has ever been able to resolve them.

This lecture situates the above problems and puzzles in their historical context, drawing on the work of many of the greatest mathematicians of the past, such as Euclid, Fermat, Euler and Gauss. Indeed, as Gauss, sometimes described as the ‘Prince of Mathematics’, has claimed: Mathematics is the Queen of the Sciences, and Number Theory is the Queen of Mathematics.

Professor Robin Wilson is Emeritus Gresham Professor of Geometry, a professor in the Department of Mathematics at the Open University, and a Stipendiary Lecturer at Pembroke College, Oxford. Professor Wilson also regularly teaches as a guest Professor at Colorado College.

Professor Wilson's academic interests lie in graph theory, particularly in colouring problems, e.g. the four colour problem, and algebraic properties of graphs. He also researches the history of mathematics, particularly British mathematics and mathematics in the 17th century and the period 1860 to 1940 and the history of graph theory and combinatorics.

Outside of the strict mathematical canon, Professor Wilson is particularly interested in the musical output of Gilbert and Sullivan - an interest that has given rise to publications and two Gresham College lectures: 'The Other Side of Sullivan' and 'A Sing-In with Gilbert and Sullivan'.

Prior to his appointment as Gresham Professor of Geometry in 2004, he was the Visiting Professor in the History of Mathematics. Upon his appointment to the Geometry chair, Professor Wilson said: "Mathematics is, and has always been a central part of human culture, and I do not believe that one can fully understand the subject if it is separated from its historical roots. My proposed lectures are designed to support this conviction."

All of Professor Wilson's past lectures can be accessed here.