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A057822 Smaller of pair of twin primes whose average is lcm(1,...,m) for some m. 0
5, 11, 59, 419, 232792559, 442720643463713815199 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
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.
LINKS
EXAMPLE
(419 + 421)/2 = 420 = lcm(1,2,3,4,5,6,7).
PROG
(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
CROSSREFS
Sequence in context: A136669 A208768 A057824 * A168243 A173875 A095150
KEYWORD
nonn,more
AUTHOR
Labos Elemer, Nov 08 2000
STATUS
approved

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Last modified March 29 09:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)