TITLE: Number of representable as sum of 2 squares
QUESTION [5 upvotes]: How to find asymptotically (or some reasonable bound, at least $ o(n) $) number of numbers, representable as a sum of squares of 2 numbers? (in case of bound I am interested in both: lower and upper bounds)
I know how to find explicitly the number of ways to represent given number in such a way. (can be found here)
Thank you!
P.S. For one lower bound you can use this problem, it'll give you somewhat $ \Omega (n^{\frac{3}{4}}) $.

REPLY [5 votes]: Posting pages 260-263 from LeVeque. The evident hair on page 262 is not part of the book proper; it evidently fell from my own head onto the scanner, and is one I could ill afford to lose. 
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