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Problem 390


Problem 390


Triangles with non rational sides and integral area

Consider the triangle with sides √5, √65 and √68. It can be shown that this triangle has area 9.

S(n) is the sum of the areas of all triangles with sides √(1+b2), √(1+c2) and √(b2+c2) (for positive integers b and c ) that have an integral area not exceeding n.

The example triangle has b=2 and c=8.

S(106)=18018206.

Find S(1010).


边长为无理数而面积为整数的三角形

考虑边长为√5、√65和√68的三角形,可以算出这个三角形的面积为9。

考虑所有边长为√(1+b2)、√(1+c2)和√(b2+c2)(b和c均为正整数),且面积为不超过n的整数的三角形,记其面积之和为S(n)。

取b=2和c=8即为上述样例三角形。

已知S(106)=18018206。

求S(1010)。