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a(n) is the 7th term in Euclid-Mullin (EM) prime sequence initiated with n-th prime.
4

%I #10 Mar 13 2015 23:08:53

%S 5,5,199,5,433,1601,31,457,7109609443,5,7,127,71,5,7,2620003,4583,

%T 1217,5,67,6729871,39334891,5,53,461,449885311,1511,197,7,22008559,19,

%U 1249,7,7,3217,7,7,3931,7,110663370509047,375155719,29,28529671,23,24603331

%N a(n) is the 7th 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 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=6};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