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%I #10 Oct 19 2017 03:14:18
%S 2,2,2,2,47,47,6047,477727,30596497,3388516667,340746580567,
%T 1763093883977,773521306107547,1142275515892937
%N Initial prime of a prime chain of length n under the iteration x->2x+3.
%C This is a special case of prime chains generated by f(x) = cx + d.
%C Is it smallest initial prime of a prime chain of length n under the iteration x->2x+3, or not? At least up to 3388516667 it is the smallest one. - _Zak Seidov_, Dec 20 2013
%H D. H. Lehmer, <a href="http://dx.doi.org/10.1112/plms/s3-14A.1.183">On certain chains of primes</a>, Proc. London Math. Soc. (3) 14a 1965 183-186.
%e a(3) = 2 since 2, 2*2+3=7 and 2*7+3=17 are primes.
%Y Cf. A057330, A057331, A083388, A084955, A084956, A084957, A084958, A084959, A084960, A084961, A128509, A134701, A134702.
%K nonn,more
%O 1,1
%A _W. Edwin Clark_, Jun 14 2003
%E More terms from _Don Reble_, Nov 07 2007
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