

A125117


First differences of A034887.


4



0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0
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OFFSET

0,1


COMMENTS

This sequence is not periodic because log(2)/log(10) is an irrational number.  T. D. Noe, Jan 10 2007
The sequence consists only of 0's and 1's. Sequence A276397 (with a 0 prefixed) is similar but differs from a(42) on. Sequence A144597 differs only from a(102) on.  M. F. Hasler, Oct 07 2016


LINKS

Table of n, a(n) for n=0..105.


FORMULA

a(n) = number_of_digits{2^(n+1)}  number_of_digits{2^(n)} with n>=0.


EXAMPLE

a(1)=0 because 2^(1+1)=4 (one digit) 2^1=2 (one digit) and the difference is 0.
a(3)=1 because 2^(3+1)=16 (two digits) 2^(3)=8 (one digit) and the difference is 1.


MAPLE

P:=proc(n) local i, j, k, w, old; k:=2; 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(wold); old:=w; else old:=w; fi; od; end: P(1000);


PROG

(PARI) a(n)=logint(2^(n+1), 10)logint(2^n, 10) \\ Charles R Greathouse IV, Oct 19 2016


CROSSREFS

Cf. A034887, A144597, A276397.
Sequence in context: A020987 A072786 A144597 * A144603 A163581 A100283
Adjacent sequences: A125114 A125115 A125116 * A125118 A125119 A125120


KEYWORD

easy,nonn,base


AUTHOR

Paolo P. Lava and Giorgio Balzarotti, Jan 10 2007


STATUS

approved



