World!OfNumbers |
WON plate 81 | |
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The palindrome Fifty Five or 55 55 is the sum of the following five consecutive square numbers ( 1 + 4 + 9 + 16 + 25 )thus making it the fifth square pyramidal number [ formula : n(n+1)(2n+1)/6 ]
55 as a Cubic Invariant 5 ^{3} + 5^{3} = 2502 ^{3} + 5^{3} + 0^{3} = 1331 ^{3} + 3^{3} + 3^{3} = 5555 is the tenth Fibonacci number 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...55 is the fourth palindromic triangular number 1, 3, 6, 55, 66, 171, ...55 is the sum of the first ten numbers 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 55 is expressible as the sum of five consecutive integers 9 + 10 + 11 + 12 + 13 55 is the sum of two consecutive numbers and powers Note that 67 – 12 equals 55 !55 is expressible as the sum of two consecutive integers 27 + 28 55 is the fourth Kaprekar number
55 can be multiplied with 10 consecutive odd numbersfrom 91 to 109 and all the products will be palindromic !Palindromes 5005 up to 5995.( From Clifford A. Pickover, “Wonders of Numbers”, Chapter 57, p. 141 ) | ||||||

A000081 Prime Curios! Prime Puzzle Wikipedia 81 Le Nombre 81 Numberland 81 |

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