%I A090096
%S A090096 4,1194649,121,1194649,4
%N A090096 Least pseudoprime belonging to base n which pseudoprime is a true power 
               of a prime number; smallest prime-power pseudoprime to base n.
%F A090096 a[n]=Min{x; Mod[ -1+n^(x-1), x where x is true-power-of-prime}
%e A090096 n=2: -1+2^(1092.1094)=K.1093.1093=K.1194649;
%e A090096 n=4k+1: a[4k+1]=4; for a[k]=9 see A090097;a[k]=25 see A090098.
%e A090096 some large values:
%e A090096 a(12)=2693.2693;a(20)=78961; a(52)=219521;a(56)=418609=647^2;
%e A090096 a(58)=17161;a(84)=26569;a(104)=97969; a(119)=3031081;
%e A090096 Stiff bases below 100 are: 6,15,34,36,39,47,59,66,72,83,86,87,88,90,92,
               95
%t A090096 t=list-of-true-p-powers-generated-independently lf[x_] := Length[FactorInteger[x]] 
               base=6;Do[s=Mod[ -1+base^(Part[t, n]-1), Part[t, n]]; If[Equal[s, 
               0], Print[Part[t, n]]], {n, 1, Length[t]}]
%Y A090096 Cf. A007535, A090086.
%Y A090096 Sequence in context: A058430 A079286 A124119 this_sequence A046362 A144122 
               A058424
%Y A090096 Adjacent sequences: A090093 A090094 A090095 this_sequence A090097 A090098 
               A090099
%K A090096 nonn
%O A090096 1,1
%A A090096 Labos E. (labos(AT)ana.sote.hu), Dec 01 2003