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Product of consecutive (Posted on 2024-09-11) Difficulty: 3 of 5
Find all integers n such that n4-8n+15 is product of two consecutive integers.

No Solution Yet Submitted by Danish Ahmed Khan    
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Some Thoughts same | Comment 2 of 3 |
Testing for n up to 10^6, I found the same 2 solutions as Charlie.

n f(n) 
3 72 = 8*9
5 600 = 24*25

-----------
def f(n):
    return n**4 - 8*n + 15

big = 1000000
conprods = [k*(k+1) for k in range(big)]

for n in range(big):
    if f(n) > conprods[-1]:
        print('too big', conprods[-1],n, f(n))
        break
    if f(n) in conprods:
        print(n, f(n), int(f(n)**.5))

  Posted by Larry on 2024-09-11 11:23:08
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