Is it possible to write down 1,2,3..100 in some order (one after an other), such that the sum of any two adjacent numbers is a prime number?
Is it possible to write all integer from 1 to 10 in a row in some order such that any two adjacent number add up to a prime number ?
First 17 positive integers (1..17) are rearranged into a sequence such that the sum of any two adjacent terms is a perfect square.
What is the sum of the first and last terms of this sequence?
Using 1, 2, 3, 4 & 5 in any order and the operators + - % * each exactly once what is the greatest possible value that you can make?
Four different prime numbers 5, 7, 17 and 19 such that the sum of any three of them is also a prime. Are there 5 different positive primes such that the sum of any three of them is also a prime?