Radio 4 maths police *More or Less *took time off from calling out journalists and deputy prime ministers for their misuse of statistics this series to sneak a hidden maths puzzle into their show. The first five episodes were “brought to us by” the numbers, respectively, **1**, **49**, **100**, **784** and **1444**. Listeners were invited to work out what number would bring us the final episode.

This Friday, the answer was revealed. In a fitting tribute to the programme’s ethos, the episodes were brought to you by the “happy squares”; square numbers whose iterated digit-square-sum terminates at 1. Readers who will only accept integer sequence facts presented in terms of Sloane’s OEIS may like to think of this as the intersection of sequences A007770 and A000290. There was only one correct entry; listen to Friday’s episode to find out who won.

### More information

Listen again to the episode where the solution and winner were announced

Presumably ‘the happy squares’ needs adding to the OEIS?