1, 11, 21, 1211, 111221, 312211...
and so on. This is a sequence we were shown at MathsJam and had fun trying to work out what on earth was going on. It led to some excellent mathematical discussion trying to work it out. We noticed some entirely irrelevant things like the first five numbers in the sequence the digits add up and follow a Fibonacci sequence but it then falls down at the sixth.
I thought this would be a great little brain-teaser, either as a starter or extension for higher ability upper key stage two children to get stuck in to. I can see great potential for lots of mathematical talk as they try to work out what is happening.
Want a clue?
Say the digits.