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%I #15 Jan 18 2025 03:12:50
%S 14,20,200,98,42,132,908,432,1040,290,48,224,1370,462,146,110,398,402,
%T 152,264,770,1322,3030,692,1106,2840,1680,1328,7752,5180,1520,1868,
%U 578,1064,1286,3692,2282,1158,1832
%N Least K such that K*(prime(10*n)^(10*n))-1 is prime with prime(n)=n-th prime.
%t s={};Do[k=0;Until[PrimeQ[k*Prime[10n]^(10n)-1],k++];AppendTo[s,k],{n,39}];s (* _James C. McMahon_, Jan 17 2025 *)
%o (PARI) a(n) = {my(k=1); while (!ispseudoprime(k*(prime(10*n)^(10*n))-1), k++); k;} \\ _Michel Marcus_, Sep 16 2019
%Y Cf. A129243, A129245.
%K nonn,more,changed
%O 1,1
%A _Pierre CAMI_, Apr 05 2007
%E a(26)-a(39) from _James C. McMahon_, Jan 17 2025