Which of the following are true?
1:for every positive integer m, there is a positive integer n such that m+n+1 is a perfect square.
2:for every positive integer m, there is a positive integer n such that mn+1 is a perfect cube
3:for every positive integer m, there is a positive integer n such that m+n+1 is a perfect cube
4:for every positive integer m, there is a positive integer n such that mn+1 is a perfect square