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A103783 Primes of the form primorial P(k)*n-1 with minimal n, n>0, k>=2. 4
5, 29, 419, 2309, 30029, 1021019, 19399379, 669278609, 38818159379, 601681470389, 14841476269619, 304250263527209, 235489703970060539, 1844669347765474229, 228124109340330313109, 24995884552004764307909 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Weak conjecture: sequence is defined for all k>=2; strong conjecture: n<(prime(k))^2;

Smallest prime p such that the prime factorization of p+1 contains the first n+1 primes. - R. J. Mathar, Jul 03 2012

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

P(2)*1-1=5 is prime, so a(2)=5;

P(9)*3-1=669278609 is prime, so a(9)=669278609;

MATHEMATICA

nmax = 2^2048; npd = 2; n = 2; npd = npd*Prime[n]; While[npd < nmax, tt = 1; cp = npd*tt - 1; While[(tt <= (Prime[n])^2) && (! (PrimeQ[cp])), tt = tt + 1; cp = npd*tt - 1]; Print[cp]; n = n + 1; npd = npd*Prime[n]]

CROSSREFS

Cf. A002110, A103515, A103782, A073917, A214089.

Sequence in context: A216027 A087899 A202759 * A103515 A198054 A202758

Adjacent sequences:  A103780 A103781 A103782 * A103784 A103785 A103786

KEYWORD

nonn

AUTHOR

Lei Zhou, Feb 15 2005

STATUS

approved

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Last modified May 5 23:41 EDT 2021. Contains 343579 sequences. (Running on oeis4.)