Keith Numbers

Bid for this paper on ebay: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=221156224355

Professor Copeland on Keith numbers, clusters and "reverse Keiths".

And before commenting on the merits of "recreational maths" - hear what Ed says.
Ed tweets at https://twitter.com/ProfEdCopeland

Keith Numbers are also known as repfigit numbers (repetitive Fibonacci-like digit).

We also spoke with Mike Keith about his numbers and he issued a playful challenge:

"There are many variations on this idea that you can imagine. For example, for a 3-digit number, instead of the next term being a+b+c (a,b,c being the three previous terms) it could be a+2b+3c, or a^2 + b + c or even more fancifully, 2a + b + the cth prime number. You could think up your own version, and name it after yourself!"