cp's OEIS Frontend

A290725 Numbers with 3k digits for some k such that the first k digits minus the middle k digits equals the last k digits.

%I A290725 #17 Feb 25 2020 13:45:44
%S A290725 101,110,202,211,220,303,312,321,330,404,413,422,431,440,505,514,523,
%T A290725 532,541,550,606,615,624,633,642,651,660,707,716,725,734,743,752,761,
%U A290725 770,808,817,826,835,844,853,862,871,880,909,918,927,936,945,954,963,972,981,990,100010,100109,100208,100307
%N A290725 Numbers with 3k digits for some k such that the first k digits minus the middle k digits equals the last k digits.
%H A290725 Robert Israel, <a href="/A290725/b290725.txt">Table of n, a(n) for n = 1..10000</a>
%e A290725 987654333 is a member because 987-654=333.
%p A290725 N:= 100: # to get the first N terms
%p A290725 count:= 0:
%p A290725 Res:= NULL:
%p A290725 for d from 1 while count < N do
%p A290725   for x1 from 10^(d-1) to 10^d-1 while count < N do
%p A290725     for x2 from 0 to x1 while count < N do
%p A290725       x3:= x1 - x2;
%p A290725       count:= count+1;
%p A290725       Res:= Res, x1*10^(2*d)+x2*10^d+x3;
%p A290725 od od od:
%p A290725 Res; # _Robert Israel_, Aug 09 2017
%t A290725 kd3Q[n_]:=Module[{c=FromDigits/@Partition[IntegerDigits[n], IntegerLength[ n]/3]},c[[1]]-c[[2]]==c[[3]]]; Table[Select[Range[10^(3n-1),10^(3n)-1], kd3Q],{n,2}]//Flatten (* _Harvey P. Dale_, Feb 25 2020 *)
%Y A290725 A286846 is a subsequence.
%K A290725 nonn,base
%O A290725 1,1
%A A290725 _N. J. A. Sloane_, Aug 09 2017
%E A290725 More terms from _Robert Israel_, Aug 09 2017