cp's OEIS Frontend

A102673 Number of digits >= 4 in decimal representation of n.

%I A102673 #25 Feb 01 2023 12:28:08
%S A102673 0,0,0,0,1,1,1,1,1,1,0,0,0,0,1,1,1,1,1,1,0,0,0,0,1,1,1,1,1,1,0,0,0,0,
%T A102673 1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,1,1,1,1,2,2,2,2,2,2,1,1,1,1,2,2,2,2,
%U A102673 2,2,1,1,1,1,2,2,2,2,2,2,1,1,1,1,2,2,2,2,2,2,1,1,1,1,2,2,2,2,2,2,0,0,0,0,1
%N A102673 Number of digits >= 4 in decimal representation of n.
%C A102673 a(n) = 0 iff n is in A007090 (numbers in base 4). - _Bernard Schott_, Feb 01 2023
%H A102673 Hieronymus Fischer, <a href="/A102673/b102673.txt">Table of n, a(n) for n = 0..10000</a>
%F A102673 From _Hieronymus Fischer_, Jun 10 2012: (Start)
%F A102673 a(n) = Sum_{j=1..m+1} (floor(n/10^j + 3/5) - floor(n/10^j)), where m = floor(log_10(n)).
%F A102673 G.f.: g(x) = (1/(1-x))*Sum_{j>=0} (x^(4*10^j) - x^(10*10^j))/(1 - x^10^(j+1)). (End)
%p A102673 p:=proc(n) local b,ct,j: b:=convert(n,base,10): ct:=0: for j from 1 to nops(b) do if b[j]>=4 then ct:=ct+1 else ct:=ct fi od: ct: end: seq(p(n),n=0..125); # _Emeric Deutsch_, Feb 22 2005
%t A102673 Table[Total@ Take[DigitCount@ n, {4, 9}], {n, 0, 104}] (* _Michael De Vlieger_, Aug 17 2017 *)
%Y A102673 Cf. A027868, A054899, A055640, A055641, A102669-A102685, A117804, A122840, A122841, A160093, A160094, A196563, A196564. Partial sums see A102674.
%Y A102673 Cf. A000120, A000788, A007090, A023416, A059015 (for base 2).
%K A102673 nonn,base,easy
%O A102673 0,45
%A A102673 _N. J. A. Sloane_, Feb 03 2005
%E A102673 More terms from _Emeric Deutsch_, Feb 22 2005