%I A056210
%S A056210 11,251,1061,1451,1901,1931,2381,3181,3491,3851,4621,4861,5261,6101,
%T A056210 6491,6581,6781,7331,8101,9941,10331,10771,11251,11261,11411,12301,
%U A056210 14051,14221,14411,15091,15131,16061,16141,16301,16651,16811,16901
%N A056210 Primes p for which the period of reciprocal = (p-1)/5.
%C A056210 Cyclic numbers of the fifth degree (or fifth order): the reciprocals 
               of these numbers belong to one of five different cycles. Each cycle 
               has the (number minus 1)/5 digits.
%H A056210 T. D. Noe, <a href="b056210.txt">Table of n, a(n) for n=1..1000</a>
%H A056210 <a href="Sindx_1.html#1overn">Index entries for sequences related to 
               decimal expansion of 1/n</a>
%t A056210 f[n_Integer] := Block[{ds = Divisors[n - 1]}, (n - 1)/Take[ ds, Position[ 
               PowerMod[ 10, ds, n], 1] [[1, 1]]] [[ -1]]]; Select[ Prime[ Range[4, 
               2000]], f[ # ] == 5 &]
%Y A056210 Cf. A001913, A097443, A055628, A056157, A056211-A056217, A098680
%Y A056210 Sequence in context: A041223 A041220 A098672 this_sequence A089298 A012154 
               A009055
%Y A056210 Adjacent sequences: A056207 A056208 A056209 this_sequence A056211 A056212 
               A056213
%K A056210 nonn
%O A056210 1,1
%A A056210 Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 02 2000
%E A056210 Entry revised by N. J. A. Sloane (njas(AT)research.att.com), Apr 30 2007