In 2013-2014, author (click here) wrote natural numbers in increasing and decreasing orders of 1 to 9 using only basic operations. See below some examples:

For more details and extension work by other see the following link:

The above study include the natural numbers till 300000. In some case factorials and or square-roots are used. There are only four numbers where we used square-root. All other numbers are basic operation incluing factorials. See below these four numbers:

To see the whole work up to 300.000 numbers refer the following links:

Crazy Representations: Extention to Half a Million Natural Numbers

Recently, the author extended the above work up to half-million, i.e., 500000 numbers in increasing and decreating orders of 1 to 9 and 9 to 1. Most of numbers are by use of factorials. There are only few numbers where the square-root is also applied. See below:

  • Increasing Order
  • Decreasing Order
  • Missing Numbers: Still there are 7 missing numbers. Out of them 4 are in the increasing case and 3 are in the decreasing case. See below these numbers:
    • Increasing order missing: 469786, 469883, 474686, 499370
    • Decreasing order missing: 431588, 464854, 468310.

These numbers can be writtern in terms of Triangular numbers:

  • Increasing order
  • 469786:=1-T(2+3)+T(4+5)T(6(7+8+9));
  • 469883:=-1-T(2+T(T(T(3))))+(T(T(4))-T(T(T(5))))(T(T(6))-T(7+8+9));
  • 474686:=(1+T(2+3))(T(T(4))-5+T(T(T(6))))+T(T(7+8+9));
  • 499370:=-1+T(T(T(2+T(3))))+4(T(5)+T(T(6))T(7+8+9));
  • Decreasing order
  • 431588:=-9+T(T(T(8)+7)+6+5)-T(4)-T(T(T(3+2+1)));
  • 464854:=-9+8-T(T(7))+6+T(T(54))T(3+2+1);
  • 468310:=-9-T(T(8))+T(T(7))T(T(6))5+T(4+3+2+1);

Among 300.001 to 500.000 there are 200.000 numbers. The whole work we have divided in folloing five parts:

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