cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

101, 110, 202, 211, 220, 303, 312, 321, 330, 404, 413, 422, 431, 440, 505, 514, 523, 532, 541, 550, 606, 615, 624, 633, 642, 651, 660, 707, 716, 725, 734, 743, 752, 761, 770, 808, 817, 826, 835, 844, 853, 862, 871, 880, 909, 918, 927, 936, 945, 954, 963, 972, 981, 990, 100010, 100109, 100208, 100307
Offset: 1

Views

Author

N. J. A. Sloane, Aug 09 2017

Keywords

Examples

			987654333 is a member because 987-654=333.
		

Crossrefs

A286846 is a subsequence.

Programs

  • Maple
    N:= 100: # to get the first N terms
    count:= 0:
    Res:= NULL:
    for d from 1 while count < N do
      for x1 from 10^(d-1) to 10^d-1 while count < N do
        for x2 from 0 to x1 while count < N do
          x3:= x1 - x2;
          count:= count+1;
          Res:= Res, x1*10^(2*d)+x2*10^d+x3;
    od od od:
    Res; # Robert Israel, Aug 09 2017
  • Mathematica
    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 *)

Extensions

More terms from Robert Israel, Aug 09 2017