Search results
Results From The WOW.Com Content Network
This happens trivially when n is a palindromic number; the nontrivial reverse divisors are 1089, 2178, 10989, 21978, 109989, 219978, 1099989, 2199978, ... (sequence A008919 in the OEIS ).
The reverse-and-add process produces the sum of a number and the number formed by reversing the order of its digits. For example, 56 + 65 = 121. As another example, 125 + 521 = 646. Some numbers become palindromes quickly after repeated reversal and addition, and are therefore not Lychrel numbers.
A palindromic number (also known as a numeral palindrome or a numeric palindrome) is a number (such as 16361) that remains the same when its digits are reversed.In other words, it has reflectional symmetry across a vertical axis.
An emirp (an anadrome of prime) is a prime number that results in a different prime when its decimal digits are reversed. [1] This definition excludes the related palindromic primes.
1089 is widely used in magic tricks because it can be "produced" from any two three-digit numbers. This allows it to be used as the basis for a Magician's Choice.For instance, one variation of the book test starts by having the spectator choose any two suitable numbers and then apply some basic maths to produce a single four-digit number.
If the last digit in the number is 5, then the result will be the remaining digits multiplied by two, plus one. For example, the number 125 ends in a 5, so take the remaining digits (12), multiply them by two (12 × 2 = 24), then add one (24 + 1 = 25). The result is the same as the result of 125 divided by 5 (125/5=25). Example. If the last ...
The generalization to radix representations, for >, and to =, is a digit-reversal permutation, in which the base-digits of the index of each element are reversed to obtain the permuted index. The same idea can also been generalized to mixed radix number systems.
The Luhn mod N algorithm generates a check digit (more precisely, a check character) within the same range of valid characters as the input string. For example, if the algorithm is applied to a string of lower-case letters (a to z), the check character will also be a lower-case letter.