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

1, 2, 2, 2, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648, 4294967296

Offset: 1

Author

Michel Lagneau, Dec 30 2009, Apr 22 2010

Keywords

• nonn
• base

Examples

			{A175555} = {5, 25, 375, 625, 59375, ...} =>
a(1) = 1 because A175555(1) = 5 occurs with the period 1 in the sequence A175555;
a(2) = 2 because A175555(2) = 25 occurs with the period 2 in the sequence A175555;
a(3) = 2 because A175555(3) = 375 occurs with the period 2 in the sequence A175555.
		

Crossrefs

Cf. A002379, A170828, A175555, A170827.

Programs

Maple

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:

Formula

a(n) = 2^(n-4) if n > = 5.

Extensions

More terms and edits. - Michel Lagneau, Jul 14 2012