The sum of the reciprocal of the square root of all the positive integers up to n is denoted by F(n), that is:

F(n) = 1+1/√2 + 1/√3 +...+ 1/√n

Determine the maximum value of n such that the integer part of the base ten expansion of F(n) DOES NOT exceed 2012.

*** For an extra challenge, solve this puzzle without using a computer program.

(In reply to re(2): computer solution by Charlie)

I agree that the computer calcultion evaluated the correct sum-

what I did is to get an approximated result without any external aid

(KS called it "an extra challenge").Apparently I came within 0.14 percent of the true value.

It took about a minute.

I'm happy.

Posted by Ady TZIDON on 2012-03-17 03:18:45