## Reverse Perfect Square Dates, Dr. Inan's New Discovery

Aziz S. Inan, Professor of Electrical Engineering, recently discovered "reverse perfect square dates." According to Inan, Sunday, December 12, 2010 was what he calls a "reverse perfect square date," the first to occur in the 21st century since the *reverse* of the full date number of this date written as a single eight-digit number as 12122010 which equals 01022121 is a perfect square number, that is, 01022121 = 1011 x 1011!

There are only three reverse perfect square dates to occur in this century. December 12, 2010 is the first one.
The other two are December 14, 2030 (since the reverse of 12142030 is 03024121 = 1739 x 1739) and October 20, 2062 (since the reverse of 10202062 is 26020201 = 5101 x 5101). The 20th century had only four reverse perfect square dates and the 18th and the 19th century had only two each. (Interestingly enough, December 12 was also a reverse perfect square date in 1951 since 15912121 = 3989 x 3989.) The 22nd and 23rd centuries will each have only two as well.

So, reverse perfect square dates are extremely rare. (See picture above.)

Inan says that December 12, 2010 also coincides with the 223rd birthday of the State of Pennsylvania (Pennsylvania officially became the 2nd U.S. State on December 12, 1787). He found some interesting and fun number connections between numbers 12122010, 223, and Pennsylvania's State's birth date December 12, 1787.

Inan's discovery, reverse perfect square dates, and his other recreational number-connection findings related to Pennsylvania State's 223rd birthday were covered in national newspapers including *USA Today*, *Philadelphia Inquirer*, *Pittsburgh Post-Gazette*, *Pittsburgh Tribune-Review*, and *Philadelphia Daily News*. The links are below.

http://content.usatoday.com/communities/sciencefair/post/2010/12/pennsylvania-birthday-provides-math-fun/1

http://www.philly.com/philly/news/breaking/20101210_Its_an_auspicious_date__Happy_Birthday__Pa__.html

http://www.post-gazette.com/pg/10347/1110354-454.stm

http://www.pittsburghlive.com/x/pittsburghtrib/news/s_713402.html

In 2009, Inan discovered "perfect square dates." Inan first published and reported this discovery in early part of 2009 in the University of Portland student newspaper *The Beacon*.

http://www.upbeacon.net/2.10850/century-of-squares-1.1512991

http://www.upbeacon.net/2.10850/a-numerical-milestone-no-foolin-1.1512897

Inan's second discovery, "reverse perfect square dates," is somewhat related to his first discovery of "perfect square dates," however, it is completely a new discovery.

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