12 means I x 1, 22 means 2 x 2, 32means 3 x 3, and so forth. 12+ 22+ 32+ 42 + ... + 252= 5525, and 22+ 42+ 62 + 82 + ... + 502 = N. Find the value of N.

Now we have been told the answer is 22,100; but I don't know how to get there the fast way, apart from actually doing the equation fo each even number until I get to 50. And then adding them all up!

Would anyone be able to explain to a me? Thank you.