Squares either way
Whether you write dates in the order day.month.year or month.day.year (in each case with two digits for each element), 04.04.01 represents 4 April 2001, and it is a square date because 40401 is the square of 201.
In addition to 4 April 2001, there is one other date in this century that is written in exactly the same way in each order and is also a square date. 1) What is that date? 2) What is the next date after today that is a square date if written in the order day.month.year? 3) What is the next date after today that is a square date if written in the order month.day.year? Give each answer in the form of 4 April 2001.
WIN 拢15 will be awarded to the sender of the first correct answer opened on Wednesday 13 November. The Editor鈥檚 decision is final. Please send entries to Enigma 1771, New 杏吧原创, Lacon House, 84 Theobald鈥檚 Road, London WC1X 8NS, or to enigma@newscientist.com (please include your postal address).
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Answer to 1765 Repeating digits: The sum of the numbers is 689
The winner Dan Sattary-Javid of Reigate, Surrey, UK