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A057822
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Smaller of pair of twin primes whose average is lcm(1,...,m) for some m.
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0
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OFFSET
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1,1
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COMMENTS
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Known values of m such that lcm(1,...,m) is a twin prime mean value are as follows: {3,4,5,6,7,19,20,21,22,47,48}.
No more such primes occurs below m < 2000.
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LINKS
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EXAMPLE
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(419 + 421)/2 = 420 = lcm(1,2,3,4,5,6,7).
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PROG
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(PARI) lista(nn=50) = {for (i=1, nn, if (isprimepower(i), if (isprime(p=lcm([2..i])-1) && isprime(p+2), print1(p, ", ")); ); ); } \\ Michel Marcus, Aug 25 2019
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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