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 A068489 m for which p(m) is the least prime dividing #p(n) - 1, i.e., one less than primorial n-th prime (A057588). 1
 3, 10, 5, 343, 3248, 18, 16, 12, 22, 20324, 50, 9414916809095, 13120, 43, 8481, 1200361259, 196, 38, 10326732314, 65, 38, 34 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS Since #P13 - 1 is a prime, see A006794, we need the number of primes less than or equal to #P13 - 1. The sequence continues 13120,43,8481,1200361259,196,38,10326732314,65,38,34, a(24) = pi(23768741896345550770650537601358309). [Donovan Johnson, Dec 08 2009] 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, 2012 - From N. J. A. Sloane, Jun 13 2012 Hisanori Mishima, Factorization results #Pn (Primorial) - 1 FORMULA PrimePi(A057713) MATHEMATICA Do[ Print[ PrimePi[ FactorInteger[ Product[ Prime[k], {k, 1, n}] - 1] [[1, 1]]]], {n, 2, 22} ] CROSSREFS Cf. A068488. Sequence in context: A281220 A280529 A281279 * A088337 A195919 A275741 Adjacent sequences:  A068486 A068487 A068488 * A068490 A068491 A068492 KEYWORD hard,more,nonn AUTHOR Lekraj Beedassy, Mar 11 2002 EXTENSIONS Edited and extended by Robert G. Wilson v, Mar 12 2002 a(13) from Donovan Johnson, Dec 08 2009 STATUS approved

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Last modified January 15 23:42 EST 2019. Contains 319184 sequences. (Running on oeis4.)