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Little math problems September 2018
09-27-2018, 11:45 PM
Post: #17
RE: Little math problems September 2018
Hi, pier4r

I think my math is right ...

Second formula is to check sum of cubes = a perfect square
Since both terms are the same, binary exponent = 1 + 3 * (6n + 1) = 18 n + 4
Sum of cubes binary exponent is even, thus perfect square.

You can also think of 26n+1 = 2 * (2n)6, so k = 2n

If (a, b) is a solution, sum of squares of (k6 a, k6 b) = cube * k12 , also a cube
Similarly, sum of cubes of (k6 a, k6 b) = square * k18, still a square.

Actually, k can be any integers, not just 2n Smile
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RE: Little math problems September 2018 - Albert Chan - 09-27-2018 11:45 PM



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