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A068488
m for which p(m) is the least prime dividing #p(n) + 1, i.e., primorial n-th prime augmented by 1 (A005234).
1
2, 4, 11, 47, 344, 17, 8, 69, 66, 67, 8028643011, 42, 18, 39, 162, 21, 59, 48, 2311331257, 179, 369, 2477, 23289, 32, 172011, 75668, 342, 35, 28757, 356411, 243, 297, 152
OFFSET
1,1
COMMENTS
Since #P34 + 1 has two rather large factors, we need the number of primes less than or equal to 678279959005528882498681487.
LINKS
R. Mestrovic, Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC--2012) and another new proof, arXiv preprint arXiv:1202.3670 [math.HO], 2012-2018. - From N. J. A. Sloane, Jun 13 2012
FORMULA
a(n) = PrimePi(A051342).
MATHEMATICA
Do[ Print[ PrimePi[ FactorInteger[ Product[ Prime[k], {k, 1, n}] + 1] [[1, 1]]]], {n, 1, 20} ]
CROSSREFS
Cf. A068489.
Sequence in context: A174632 A307592 A091240 * A096119 A117157 A267013
KEYWORD
nonn,hard,more
AUTHOR
Lekraj Beedassy, Mar 11 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Mar 12 2002
STATUS
approved