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%I #16 May 05 2018 14:28:38
%S 2,3,5,29,11,7,13,37,17,79,23,4129,193,2593,101,19,39163,577,26431,
%T 131,308798542881428667318174028327605372989,103,163,179,293,127,6287,
%U 683437,31,89,13590243019242466336587034391,113,2207,59,109,223,2351
%N Smallest prime factor in product of previous terms +1 or -1.
%C A variant of the Euclid-Mullin construction.
%C This sequence is listed on the OEIS wiki page "OEIS sequences needing factors" and on the corresponding thread on mersenneforum.org. - _M. F. Hasler_, Mar 21 2013
%H Donovan Johnson, <a href="/A102926/b102926.txt">Table of n, a(n) for n = 1..111</a>
%F a(n) = least prime factor of b(n)^2-1, where b(n) = product a(k), 0<k<n, = A102927.
%e a(5)=11 because 2*3*5*29=870, 869=11*79, 871=13*67.
%e a(31) = 13590243019242466336587034391 because this is the least prime factor of A102927(30)+1. The least prime factor of A102927(30)-1 is 44989026625856465412069667987. Remarkably, both are 29-digit numbers. - _David Wasserman_, Apr 15 2008
%t spf[{p_,a_}]:=With[{f=FactorInteger[p^2-1][[1,1]]},{p*f,f}]; NestList[ spf,{2,2},36][[All,2]] (* _Harvey P. Dale_, May 05 2018 *)
%Y Cf. A000945, A000946, A005265, A102927.
%K nonn
%O 1,1
%A _Marc LeBrun_, Jan 19 2005
%E More terms from _Don Reble_, Jan 23 2005, corrected Sep 26 2006
%E Further terms from _David Wasserman_, Apr 15 2008
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