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%I #5 May 21 2016 22:53:35
%S 2,17,145,577,5185
%N Smallest base b such that A273339(b) = A002808(n), i.e., smallest base b > 1 such that the n-th composite number is the smallest "non-Wieferich pseudoprime" to base b.
%o (PARI) composite(n) = my(i=0, c=2); while(1, if(!ispseudoprime(c), i++); if(i==n, return(c)); c++)
%o a273339(n) = forcomposite(c=1, , if(Mod(n, c^2)^(c-1)!=1, return(c)))
%o a(n) = my(b=2, c=composite(n)); while(a273339(b)!=c, b++); b
%Y Cf. A273339.
%K nonn,more
%O 1,1
%A _Felix Fröhlich_, May 20 2016