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A057705 Primorial primes: primes p such that p+1 is a primorial number (A002110). 18
5, 29, 2309, 30029, 304250263527209, 23768741896345550770650537601358309, 19361386640700823163471425054312320082662897612571563761906962414215012369856637179096947335243680669607531475629148240284399976569 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..7.

C. Caldwell's The Top Twenty, Primorial.

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

FORMULA

a(n) = A002110(A057704(n)) - 1.

MATHEMATICA

lst={}; r=1; Do[p=Prime[n]; r=r*p; q=r-1; If[PrimeQ[q], (*Print[p]; *)AppendTo[lst, q]], {n, 1, 10^2}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 22 2008 *)

Select[FoldList[Times, 1, Prime[Range[70]]], PrimeQ[#-1]&]-1 (* Harvey P. Dale, Jan 27 2014 *)

PROG

(Haskell)

a057705 n = a057705_list !! (n-1)

a057705_list = filter ((== 1) . a010051) a057588_list

-- Reinhard Zumkeller, Mar 27 2013

CROSSREFS

See A006794 and A057704 (the main entries for this sequence) for more terms. Cf. A014545, A002110.

Cf. A010051; subsequence of A057588.

Sequence in context: A046842 A175905 A057706 * A237188 A086720 A056869

Adjacent sequences:  A057702 A057703 A057704 * A057706 A057707 A057708

KEYWORD

nonn,nice

AUTHOR

Labos Elemer, Oct 24 2000

STATUS

approved

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Last modified August 29 02:15 EDT 2015. Contains 261184 sequences.