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%I #6 Mar 25 2016 07:49:32
%S 9,55,85,259,781,91,2737,451,645,341,481,703,4005,4369,4371,2071,7957,
%T 8695,561,6697,15251,7107,16705,3201,34133,31609,3277,1105,16589,1891,
%U 18705,9881,13833,14701,19345,47197,26335,1729,8321,2821,2701,35371,12801,22177
%N Smallest composite c where exactly n composites d with d < c exist such that c^(d-1) == 1 (mod d) and d^(c-1) == 1 (mod c).
%C a(n) = smallest A002808(i) with A270573(i) = n for some i > 0.
%o (PARI) a(n) = forcomposite(c=1, , my(i=0); forcomposite(d=1, c-1, if(Mod(c, d)^(d-1)==1 && Mod(d, c)^(c-1)==1, i++)); if(i==n, return(c)))
%Y Cf. A270573, A270574.
%K nonn
%O 1,1
%A _Felix Fröhlich_, Mar 19 2016