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Beginning with 7, primes of the form: least multiple of the previous term followed by a 1. Beginning with 7, a(n) is the least prime of the form k*a(n-1)*10 +1.
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%I #8 Nov 15 2021 02:48:08

%S 7,71,2131,191791,5753731,575373101,17261193031,517835790931,

%T 82853726548961,28998804292136351,16239330403596356561,

%U 4384619208971016271471,526154305076521952576521

%N Beginning with 7, primes of the form: least multiple of the previous term followed by a 1. Beginning with 7, a(n) is the least prime of the form k*a(n-1)*10 +1.

%t nxt[n_]:=Module[{k=1},While[CompositeQ[10*k*n+1],k++];10*k*n+1]; NestList[ nxt,7,20] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Aug 04 2019 *)

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Jan 03 2006

%E More terms from _Joshua Zucker_, Jan 11 2006