A125122 - OEIS

%I #7 Jan 28 2015 16:19:54

%S 0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,1,0,1,0,1,0,1,0,1,0,1,0,

%T 1,0,1,0,1,0,1,0,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,1,0,

%U 1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0

%N First differences of A034888.

%C This sequence is not periodic because log(3)/log(10) is an irrational number. - _T. D. Noe_, Jan 10 2007

%F a(n)=Number_of_digits{3^(n+1)}-Number_of digits{3^(n)} with n>=0.

%e a(1)=0 because 3^(1+1)=9 (one digit) 3^1=3 (one digit) and the difference is 0

%e a(4)=1 because 3^(4+1)=243 (three digits) 3^(4)=81 (two digits) and the difference is 1

%p P:=proc(n) local i,j,k,w,old; k:=3; for i from 1 by 1 to n do j:=k^i; w:=0; while j>0 do w:=w+1; j:=trunc(j/10); od; if i>1 then print(w-old); old:=w; else old:=w; fi; od; end: P(1000);

%t Differences[IntegerLength[3^Range[0,110]]] (* _Harvey P. Dale_, Jan 28 2015 *)

%K easy,nonn,base

%O 0,1

%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Jan 10 2007