cp's OEIS Frontend

A257296 Arithmetic mean of the digits of n, multiplied by 10^(d-1) and rounded down, where d is the number of digits of n.

%I A257296 #21 Mar 11 2020 16:39:16
%S A257296 0,1,2,3,4,5,6,7,8,9,5,10,15,20,25,30,35,40,45,50,10,15,20,25,30,35,
%T A257296 40,45,50,55,15,20,25,30,35,40,45,50,55,60,20,25,30,35,40,45,50,55,60,
%U A257296 65,25,30,35,40,45,50,55,60,65,70,30,35,40,45,50,55,60,65
%N A257296 Arithmetic mean of the digits of n, multiplied by 10^(d-1) and rounded down, where d is the number of digits of n.
%C A257296 The reason for the factor 10^(d-1) in the definition is to produce an analog of A257294, i.e., give the first d digits of the mean value, for an "average" d-digit number. But since the arithmetic mean of the digits may be between 0 and 1, the situation is slightly different from the case of the geometric mean.
%C A257296 Also motivated by sequence A257829.
%H A257296 Robert Israel, <a href="/A257296/b257296.txt">Table of n, a(n) for n = 0..10000</a>
%F A257296 a(n) = floor(A007953(n)/A055642(n)*10^(A055642(n)-1))
%e A257296 For n = 12, a two-digit number, the average of the digits is 1.50000..., so a(12) = 15.
%p A257296 f:= proc(n) local d;
%p A257296      d:= ilog10(n);
%p A257296      floor(convert(convert(n,base,10),`+`)/(d+1)*10^d)
%p A257296 end proc:
%p A257296 map(f, [$0..100]); # _Robert Israel_, May 10 2015
%t A257296 Table[Floor[Mean[IntegerDigits[n]]10^(IntegerLength[n]-1)],{n,0,70}] (* _Harvey P. Dale_, Mar 11 2020 *)
%o A257296 (PARI) a(n)=sum(i=1,#n=digits(n),n[i])*10^(#n-1)\#n
%Y A257296 Cf. A004426, A004427, A007953, A055642, A257829.
%K A257296 nonn,base,easy,look
%O A257296 0,3
%A A257296 _M. F. Hasler_, May 10 2015