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a[n] is the 5th term in Euclid-Mullin (EM) prime sequence initiated with n-th prime.
4

%I #10 Mar 13 2015 23:08:32

%S 13,13,331,13,7,6163,7,571,13,10267,23,31,7,13,17,7,3,7,5227,43,7,

%T 2371,7,61,19,3,7,13,3271,13,5,37,4111,43,3,13,47,7,5011,360187,7,73,

%U 13,22003,23,7,8863,5,7,6871,181,193,7,7,11,139,3,7,1297,73,7,7,31,3,7

%N a[n] is the 5th term in Euclid-Mullin (EM) prime sequence initiated with n-th prime.

%e First term is p[n], 2nd equals 2;

%e 3rd term is A091460 as largest p-divisor of 2p+1

%e (occasionally safe primes, A005385);

%e 4th terms listed in A051614; 5th term is here in A094461;

%e 6th, 7th terms in A094462, A094463;

%t a[x_]:=First[Flatten [FactorInteger[Apply[Times, Table[a[j], {j, 1, x-1}]]+1]]];ta=Table[0, {168}];a[1]=1; Do[{a[1]=Prime[j], el=5};Print[a[el];ta[[j]]=a[el];j++ ], {j, 1, 168}];ta

%Y Cf. A000945, A005385, A051614-A051616, A051308-A051335, A093778-A093782, A094152-A094153, A094460-A094463.

%K nonn

%O 1,1

%A _Labos Elemer_, May 06 2004