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%I #10 Sep 24 2019 03:02:20
%S 1,4,1,19,16,56,80,383,235
%N Sequence of k such that starting with P(0)=7 then k(n)*P(n-1)*(k(n)*P(n-1)-1)-1 is the least prime = P(n).
%e 1*7*7-1*7-1=41 prime so k(1)=1 P(1)=41;
%e 1*41*(1*41-1)-1=1639 composite,
%e 2*41*(2*41-1)-1=6641 composite,
%e 3*41*(3*41-1)-1=15005 composite,
%e 4*41*(4*41-1)-1=26731 prime so k(2)=4 P(2)=26731;
%e 1*26731*(1*26731-1)-1=714519629 prime so k(3)=1 P(3)=714519629.
%o (PARI) P=7; for(i=1, 20, k=0; while(!ispseudoprime(t=k++*P*(k*P-1)-1), ); P=t; print1(k", ")) \\ _Michel Marcus_, Sep 16 2019 ; after A141240
%Y Cf. A141234, A141235, A141236, A141237, A141238, A141239, A141240.
%K nonn,more
%O 1,2
%A _Pierre CAMI_, Jun 16 2008
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