Original entry on oeis.org
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Select[Range[65], PrimeQ[Product[Product[Prime[i],{i,1,n}],{n,1,#}]-1]&] (* Stefan Steinerberger, Apr 12 2006 *)
A066266
Product of first n primorials + 1.
Original entry on oeis.org
3, 13, 361, 75601, 174636001, 5244319080001, 2677277333530800001, 25968760179275365452000001, 5793445238736255798985527240000001, 37481813439427687898244906452608585200000001, 7517370874372838151564668004911177464757864076000000001
Offset: 1
a(3)=361 since 361 = (2)*(2*3)*(2*3*5) + 1.
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Table[Times@@Table[Times@@Prime[Range[n]],{n,k}]+1,{k,40}] (* Jayanta Basu, May 12 2013 *)
Rest[FoldList[Times,1,Rest[FoldList[Times,1,Prime[Range[10]]]]]]+1 (* Harvey P. Dale, Sep 16 2013 *)
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a(n) = 1 + prod(k=1, n, prime(k)^(n-k+1)) \\ Andrew Howroyd, Dec 10 2024
A066267
Numbers k such that A066266(k) is prime.
Original entry on oeis.org
1, 2, 5, 12, 15, 35
Offset: 1
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t={}; Do[If[PrimeQ[Times@@Table[Times@@Prime[Range[n]],{n,k}]+1],AppendTo[t,k]],{k,35}]; t (* Jayanta Basu, May 12 2013 *)
Showing 1-3 of 3 results.
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