Bingo! Though I always heard Yogi use just "smarter than the average bear" as his catchphrase.

One of the additional tricky bits was realizing that it was "Bear-sub-i" not "bear * i" which could be "imaginary bear" or could be 1 bear when i = 1, 2 bears when i =2, etc..

But I couldn't think of how a brain is greater than a sum and quotient of imaginary bears, or now a brain is greater than (n+1)/2 bears.