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Also: Write product of first n primes as x*y with x<y and x maximal; sequence gives value of y. This was sequence A061059, which is a duplicate of this sequence. Indeed, p(n)# = primorial(n) = A002110(n) is never a square, it has N=2^n distinct divisors. Since this is an even number, the N divisors can be grouped in N/2 pairs {d(k), d(N+1-k)} with product equal to p(n)#. Obviously, one of the two is always smaller and one is larger than sqrt(p(n)#). This sequence gives the (2^(n-1)+1)-th divisor, which is the smallest one larger than sqrt(p(n)#). - M. F. Hasler, Sep 20 2011
Further terms (calculated from A182987):
a(24) = 154171363634898185,
a(25) = 1518410187442699518,
a(26) = 15259831781575946565,
a(27) = 154870358790203939190,
a(28) = 1601991507050573600715,
a(29) = 16725281357261594271714,
a(30) = 177792170427340904920562,
a(31) = 2003615968659851168928690,
a(32) = 22932432917001897051097491,
a(33) = 268417245982598363846820345,
a(34) = 3164592660873444717893657954,
a(35) = 38628776202993992477961504201,
a(37) = 5947702665851804982553152089030. - M. F. Hasler, Sep 20 2011.
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