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Seeking the middle term (Posted on 2024-05-04) Difficulty: 3 of 5
The sum of the binomial coefficients in the binomial degree expansion (x+(1/x)1/3)n is 4096. Find the middle term of the expansion.

No Solution Yet Submitted by Danish Ahmed Khan    
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Some Thoughts solution | Comment 1 of 3
Referring to Pascal's triangle, n=12
 12: [4096, [1, 12, 66, 220, 495, 792, 924, 792, 495, 220, 66, 12, 1]]

The coefficient of the middle term is 924
The power of x is (6 - 6/3) = 4
The middle term is 924*x^4

The sequence of exponents starts with 12 and ends with -4, decreasing by 4/3 in each subsequent term.

--------   program to generate Pascal's Triangle
coefs = [1,1]
power = 1
sumcoefs = sum(coefs)
coefDict = {1: [sumcoefs,coefs]}

while sumcoefs < 4100:
    power += 1
    new = [1]
    for ind, val in enumerate(coefs):
        if ind == 0:
            continue
        else:
            new.append(coefs[ind-1] + val)
    new.append(1)
    coefs = new
    sumcoefs = sum(coefs)
    coefDict[power] = [sumcoefs,coefs]
    if sumcoefs == 4096:
            print([sumcoefs,coefs])

  Posted by Larry on 2024-05-05 10:20:08
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