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a(1) = 2, a(n+1) is smallest prime factor of (2 * Product_{k=1..n} a(k)) + 1.
0

%I #8 Dec 15 2017 17:36:07

%S 2,5,3,61,7,25621,656410021,8874301,9137,1069,491,23,1031,17,19,41,

%T 197,311,1187,113,11,1249,

%U 650176342761734684441179196492094381946145205110026217821,13,43,89,239,56359,31732153,29,37,9109,907,6323,293,811,77806657

%N a(1) = 2, a(n+1) is smallest prime factor of (2 * Product_{k=1..n} a(k)) + 1.

%C Variation of the Euclid-Mullin sequence A000945.

%e a(5) is equal to 7 because 2*(2*5*3*61)+1 = 3661 = 7 * 523.

%Y Cf. A000945.

%K nonn

%O 1,1

%A _Jason Earls_, Nov 29 2002

%E a(26)-a(37) from _Robert Price_, Jul 20 2015

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Last modified September 24 11:34 EDT 2024. Contains 376196 sequences. (Running on oeis4.)