A102673 - OEIS

A102673

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

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, 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, 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

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OFFSET

0,45

COMMENTS

a(n) = 0 iff n is in A007090 (numbers in base 4). - Bernard Schott, Feb 01 2023

LINKS

Hieronymus Fischer, Table of n, a(n) for n = 0..10000

FORMULA

From Hieronymus Fischer, Jun 10 2012: (Start)

a(n) = Sum_{j=1..m+1} (floor(n/10^j + 3/5) - floor(n/10^j)), where m = floor(log_10(n)).

G.f.: g(x) = (1/(1-x))*Sum_{j>=0} (x^(4*10^j) - x^(10*10^j))/(1 - x^10^(j+1)). (End)

MAPLE

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

MATHEMATICA

Table[Total@ Take[DigitCount@ n, {4, 9}], {n, 0, 104}] (* Michael De Vlieger, Aug 17 2017 *)

CROSSREFS

Cf. A027868, A054899, A055640, A055641, A102669-A102685, A117804, A122840, A122841, A160093, A160094, A196563, A196564. Partial sums see A102674.

Cf. A000120, A000788, A007090, A023416, A059015 (for base 2).

Sequence in context: A360078 A027354 A192227 * A085297 A080972 A037814

Adjacent sequences: A102670 A102671 A102672 * A102674 A102675 A102676

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane, Feb 03 2005

EXTENSIONS

More terms from Emeric Deutsch, Feb 22 2005

STATUS

approved