

A068489


m for which p(m) is the least prime dividing #p(n)  1, i.e., one less than primorial nth 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
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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

Table of n, a(n) for n=2..23.
R. Mestrovic, Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 BC2012) 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



