Almost right-angled triangles II
Problem 224Published on Friday, 26th December 2008, 05:00 pm; Solved by 800; Difficulty rating: 75%
Let us call an integer sided triangle with sides a ≤ b ≤ c barely obtuse if the sides satisfy
a2 + b2 = c2 - 1.
How many barely obtuse triangles are there with perimeter ≤ 75,000,000?