%I #32 Jul 11 2023 08:56:55
%S 2,2,2,2,2,3,2,2,2,11,3,3,2,2,5,2,2,3,3,5,2,2,5,2,2,7,3,3,2,2,23,47,2,
%T 2,2,29,2,53,13,5,17,29,5,3,3,3,5,17,2,3,3,79,31,11,7,23,2,7,3,7,2,13,
%U 5,7,5,7,23,17,23,13,31,29,7,67,47,7,2,23,13,23,23,31,73,13,23,3,17
%N a(n) is the smallest prime such that a(1)*a(2)*...*a(n) +/- 1 is prime.
%t a[1] = 2; a[n_] := a[n] = Module[{r = Product[a[k], {k, 1, n - 1}], p = 2}, While[! PrimeQ[r*p - 1] && ! PrimeQ[r*p + 1], p = NextPrime[p]]; p]; Array[a, 100] (* _Amiram Eldar_, Jul 08 2023 *)
%Y Cf. A036014, A236465.
%K nonn
%O 1,1
%A _Dmitry Kamenetsky_, Jul 08 2023
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