1. In Memory of Nelson Rolihlahla Mandela 5 December 2013 Aziz S. Inan Donald P. Shiley School of Engineering University of Portland 5 December 2013 1

2. South African anti-apartheid revolutionary and President Nelson Rolihlahla Mandela was born on 18 July 1918 (18-07-1918). We lost this great man today, on 5 December 2013 (5-12-2013), at age 95. 5 December 2013 2

3. I dedicate these next few slides in his memory. 5 December 2013 3

4. Mandela’s death date, 5 December, expressed as 5-12, or simply as 512, is the highest-power date in each year. How? 512 = 2 9 ! Mandela died on the Highest- Power Day of the Year 5 December 2013 4 (Note that 5 December (512) is the highest-power date of each year in the day-month-year date format. However, in the month-day-year date format, the highest-power date is October 24, expressed as 1024 = 2 10 !)

5. Mandela died on a Pythagorean Day. Why? If 5 December 2013 is expressed as 5-12-13, then: 5 2 + 12 2 = 13 2 ! Mandela died on a Pythagorean Day 5 December 2013 5 Other such ascending-order Pythagorean Days in each century in day-month-year date format are 03- 04-05, 06-08-10, and 09-12-15. (Additional Pythagorean Days in the month-day-year date format are 8-15-17, 12-16-20, 7-24-25, and 10-24-26.)

6. If numbers are assigned to the letters of Mandela’s full name based on the English alphabet (let A = 1, B = 2, etc.), number 512 (representing Mandela’s death day) repeats in his full name three times: NELSON  14512191514 14 5 12 19 15 14 ROLIHLAHLA  181512981218121 18 15 12 9 8 12 1 8 12 1 MANDELA  1311445121 13 1 14 4 5 12 1 Number 512 Repeats in Mandela’s Name Three Times 5 December 2013 6

7. Number 121 repeats four times in Mandela’s full name: NELSON  14512191514 ROLIHLAHLA  181512981218121 MANDELA  1311445121 Number 121 Repeats in Mandela’s Name Four Times 5 December 2013 7

8. How? 121 = 11 x 11 = 11 2 121 + 121 + 121 + 121 = 484 = 22 x 22 22 + 22 = 44 11 2 x 44 = 11 2 x 43 + 11 2 11 2 x 43 = 5203 11 2 = 121 5122013! Four 121’s “Magically” Lead to Mandela’s Death Date 5 December 2013 8

9. Mandela’s death date, 5 December 2013, can be written as: Numerical Connection Between Mandela’s Name and Death Date 5 December 2013 9 5-12-13 Notice that numbers 523 and 11 are intertwined to result in 51213. Interestingly enough, reverse of one less than 523 is 225, which equals the sum of the numbers assigned to the letters of Nelson Rolihlahla Mandela [1]. Also, interestingly, 523 – 11 = 512 (again, 5 December).

10. You will be missed, Nelson Mandela! 5 December 2013 10 References: [1] A. S. Inan, “Happy 95 th Birthday, Nelson Rolihlahla Mandela,” July 17, 2013. http://faculty.up.edu/ainan/publications.html