Question

Does anybody know a quick, pretty way to solve this problem? I've been doing this, and I am supposed to write a solution for it, but can't come up with a less-complicated way than guess-and-check.
What is the largest 7-digit number that contains each of the digits 1 through 7 and has the property that the sum of any 2 consecutive digits is a prime number?

Answer 1

7652341

Answer 2

That's what I got, but I'm not sure how to write a solution for how I got that

Answer 3

well, go this way..
number is greatest when it starts with 7, then it will be larger than others if there is 6 after 7. prime number condition is also satisfied as 7+6=13
then check for 5, 4, 3..... i donr think there is any other way

Answer 4

sorry, don't ^^

Answer 5

sorry, don't ^^