Minimum Sum of Non-Negative Integers with Given Equation - POTW #504

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SUMMARY

The problem presented involves finding the minimum sum of non-negative integers \(a\), \(b\), \(c\), and \(d\) that satisfy the equation \(a^2 + b^2 - cd^2 = 2022\). The initial guess for the minimum sum \(s = a + b + c + d\) was calculated as 91 with values \(a = 32\), \(b = 32\), \(c = 26\), and \(d = 1\). Alternative combinations were explored, such as \(a = 33\), \(b = 31\), \(d = 1\), and \(c = 28\) yielding a sum of 93, and \(a = 45\), \(b = 1\), \(d = 2\), and \(c = 1\) resulting in a sum of 49. The discussion indicates that the initial guess did not yield the minimum sum.

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Here is this week's POTW:

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Let ##a,\,b,\,c## and ##d## be non-negative integers.

If ##a^2+b^2-cd^2=2022##, find the minimum of ##a+b+c+d##.

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Thanks for the interesting problem. I have not found the answer but I would like to guess it.
s:=a+b+c+d=a+b+d+\frac{a^2+b^2-2022}{d^2}
Guessing for minimum s that a=b and ##2a^2-2022## is least with an integer c
a=b=32, d=1, c=26
s=91
A nearby case is
a=33,b=31,d=1,c=28;\ s=93>91
However, for a>>b case
a=45,b=1,d=2,c=1;\ s=49
My guess failed. I will be glad to know the right answer.
 
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