30 lines
530 B
Python
30 lines
530 B
Python
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#!/usr/bin/env python3
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def nofdivs(n):
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sieve = [1] * n
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for p in range(2, n):
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if sieve[p] > 1:
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continue
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pw = 1
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while p**pw < n:
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for i in range(p**pw, n, p**pw):
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sieve[i] += sieve[i] // pw
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pw += 1
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return sieve
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bound = 10**5
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sieve = nofdivs(bound)
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target = 500
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for n in range(1, bound-1):
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if n % 2:
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a, b = (n + 1)//2, n
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else:
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a, b = n//2, n+1
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if sieve[a] * sieve[b] > target:
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print(a * b)
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break
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