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A057705
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Primorial primes: primes p such that p+1 is a primorial number (A002110).
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21
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5, 29, 2309, 30029, 304250263527209, 23768741896345550770650537601358309, 19361386640700823163471425054312320082662897612571563761906962414215012369856637179096947335243680669607531475629148240284399976569
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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Chris K. Caldwell's The Top Twenty, Primorial.
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FORMULA
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MATHEMATICA
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Select[FoldList[Times, 1, Prime[Range[70]]], PrimeQ[# - 1] &] - 1 (* Harvey P. Dale, Jan 27 2014 *)
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PROG
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(Haskell)
a057705 n = a057705_list !! (n-1)
a057705_list = filter ((== 1) . a010051) a057588_list
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CROSSREFS
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See A006794 and A057704 (the main entries for this sequence) for more terms.
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KEYWORD
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nonn,nice
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AUTHOR
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STATUS
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approved
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