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A325136
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The product of primes <= 2n that are strongly prime to 2n, bisection of A181836.
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1
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1, 1, 1, 1, 15, 7, 35, 165, 1001, 5005, 51051, 20995, 1616615, 1716099, 5311735, 7436429, 3234846615, 178752665, 955049953, 5277907635, 19027533679, 176684241305, 13829557433055, 18960523669087, 2180460221945005, 8784139751264163, 463717784757535, 102481630431415235
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OFFSET
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0,5
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LINKS
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FORMULA
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a(n) is squarefree.
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MAPLE
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primes := n -> select(k -> isprime(k), {$1..n}):
strong_prime_to := n -> select(k -> igcd(k, n) = 1, primes(n)) minus numtheory:-divisors(n-1):
A325136 := n -> mul(k, k in strong_prime_to(2*n)):
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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