The nerdy secret The Simpsons hides on 'prime' time television

'COMEDY," says Al Jean, "is very mathematical. Especially animation, with its precision and control."

I bow to his expertise on both subjects - he is a graduate in mathematics from Harvard University but, more famously, he is also one of the original writers of the longest-running and most successful animated TV show of all time, The Simpsons, which will have its 25th anniversary in December.

You can see the analogy - although he doesn't call it an analogy; he uses the mathematical term isomorphism. Good comedy, like a mathematical problem, has a complicated set-up and then a satisfying, unexpected reveal: "Coming up with a good joke is often like doing a proof," said Jean.

That, at least, was the explanation he gave for the fact that the writing staff of The Simpsons is full of maths geniuses, and that the show is crammed with highbrow mathematical concepts.

A book called The Simpsons and their Mathematical Secrets was published this year. It was written by Simon Singh, one of Britain's most respected science writers and the holder of a PhD in particle physics.

"We're subconsciously oozing our nerdiness into the script," said Jean.

He gives an example: one 2006 episode features a baseball game. At one point, the crowd is asked to guess the attendance, and three numbers come up: 8128, 8208 and 8191. For most viewers they are three arbitrary numbers but, for maths nerds, they are not. The first, 8128, is a so-called "perfect number": the numbers that it divides into also add up to it. Then, 8208 is a "narcissistic number": it has four digits and, if you multiply each one by itself four times, the results add up to 8208.

And 8191 is a "Mersenne prime", named after a 17th-century French mathematician. A prime number is one that can be divided only by itself and one; for many prime numbers, if you double them and add one, it makes a new prime number, a Mersenne.

Sometimes the writers let their maths-geekery take centre stage. "When we get called out for nerdiness, we tend to double down," says Jean. So one episode, a parody of the film Moneyball , revolves around the statistical analysis of baseball results. A future episode, according to Jean, has Lisa on a maths team, and features "the most complicated math jokes we can think of". - © The Daily Telegraph, London