## Lucky number

Off topic discourse and banter encouraged.
Ann
4725 Å
Posts: 11527
Joined: Sat May 29, 2010 5:33 am

### Lucky number

107777 views.png
10,7777 views.
There have been 10,7777 views of The Bridge: Discuss an Astronomy Picture of the Day as I took a look this morning.

Sounds like a lucky number.

Ann
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orin stepanek
Plutopian
Posts: 6826
Joined: Wed Jul 27, 2005 3:41 pm

### Re: Lucky number

You better run to the gas station & get yourself a lottery #!
Orin

Smile today; tomorrow's another day!

neufer
Posts: 18373
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

### The Topic of Kaprekar

Ann wrote:
Fri Jun 19, 2020 8:12 am

There have been 10,7777 views of The Bridge: Discuss an Astronomy Picture of the Day as I took a look this morning.

Sounds like a lucky number.
https://en.wikipedia.org/wiki/D._R._Kaprekar wrote:

<<Dattatreya Ramchandra Kaprekar (1905–1986) was an Indian recreational mathematician who described several classes of natural numbers including the Kaprekar, harshad and self numbers and discovered the Kaprekar's constant, named after him. Despite having no formal postgraduate training and working as a schoolteacher, he published extensively and became well known in recreational mathematics circles.

A Kaprekar number is a positive integer with the property that if it is squared, then its representation can be partitioned into two positive integer parts whose sum is equal to the original number (e.g. 45, since 452=2025, and 20+25=45, also 9, 55, 99 etc.)

Some examples of Kaprekar numbers in base 10,
are (sequence A006886 in the OEIS):

Code: Select all

``````Number 	    Square 	        Decomposition
.................................................
703 	 703² = 494209 	        494+209 = 703
2728 	2728² = 7441984 	744+1984 = 2728
5292 	5292² = 28005264 	28+005264 = 5292
7777 	7777² = 60481729 	6048+1729 = 7777``````
Art Neuendorffer