cp's OEIS Frontend

A171869 a(n) is the period of A175555(n) in the sequence {A175555}.

%I A171869 #14 Jan 04 2013 15:00:43
%S A171869 1,2,2,2,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,
%T A171869 65536,131072,262144,524288,1048576,2097152,4194304,8388608,16777216,
%U A171869 33554432,67108864,134217728,268435456,536870912,1073741824,2147483648,4294967296
%N A171869 a(n) is the period of A175555(n) in the sequence {A175555}.
%F A171869 a(n) = 2^(n-4) if n > = 5.
%e A171869 {A175555} = {5, 25, 375, 625, 59375, ...} =>
%e A171869 a(1) = 1 because A175555(1) = 5 occurs with the period 1 in the sequence A175555;
%e A171869 a(2) = 2 because A175555(2) = 25 occurs with the period 2 in the sequence A175555;
%e A171869 a(3) = 2 because A175555(3) = 375 occurs with the period 2 in the sequence A175555.
%p A171869 nn:=2000:Digits:=nn:T:=array(1..nn):for n from 1 to nn do: T[n]:= irem(floor((1.5 ^n)*10^n),10^n): od: for a from 1 to nn do: z1:=T[a]: ii:=0:k:=0:for b from a+1 to nn while(ii)=0 do:k:=k+1:  z2:=irem(T[b],10^a): if z1=z2 then ii:=1:printf(`%d, `, k): else fi:od:od:
%Y A171869 Cf. A002379, A170828, A175555, A170827.
%K A171869 nonn,base
%O A171869 1,2
%A A171869 _Michel Lagneau_, Dec 30 2009, Apr 22 2010
%E A171869 More terms and edits. - _Michel Lagneau_, Jul 14 2012