October 2009
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There is a saying (wrongly) attributed to Charles Darwin:
A mathematician is a blind man in a dark room looking for a black cat which isn't there.
The sequence is the number of letters in each word, so its completion is 4, 5 (or 5, 5 is you count the apostrophe).
Thanks to one of our solvers which was inspired to make this cute lol (external link).
If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com