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A084401 n-th partial product + 1 is a prime, where a(n)>1 for n>1. 3

%I

%S 1,2,2,3,3,2,6,3,2,4,7,7,3,8,6,2,3,6,9,6,14,19,11,4,4,19,4,13,3,10,13,

%T 15,4,11,9,2,5,26,19,52,21,20,63,4,19,17,6,29,19,3,5,51,11,14,15,7,12,

%U 44,34,7,21,32,3,22,10,19,19,7,20,4,22,4,17,35,47,40,14,5,14,36,39,16

%N n-th partial product + 1 is a prime, where a(n)>1 for n>1.

%C Except for the first term, same as A036012. - _David Wasserman_, Dec 22 2004

%e 1+1 =2, 1*2+1=3, 1*2*2 +1=5 etc. are primes.

%t a[1] = p = 1; a[n_] := a[n] = Catch[For[k = 2, True, k++, If[PrimeQ[p*k + 1], p = p*k; Throw[k]]]]; Table[a[n], {n, 1, 82}] (* _Jean-Fran├žois Alcover_, May 14 2012 *)

%Y Cf. A084402.

%K nonn

%O 1,2

%A _Amarnath Murthy_, May 31 2003

%E More terms from _David Wasserman_, Dec 22 2004

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Last modified May 21 06:36 EDT 2022. Contains 353889 sequences. (Running on oeis4.)