Less mixin for all 4 margins (top,right,bottom.left)

How can I write this css as an less mixin that generate all those classes automatically:

  .class1x{margin-top:1px;}
  .class2x{margin-right:1px;}
  .class3x{margin-bottom:1px;}
  .class4x{margin-left:1px;}
===========================================
  .class1y{margin-top:2x;}
  .class2y{margin-right:2px;}
  .class3y{margin-bottom:2px;}
  .class4ymargin-left:2px;}    
===========================================
  .class1n{margin-top:n..px;}
  .class2n{margin-right:n..px;}
  .class3n{margin-bottom:n..px;}
  .class4nmargin-left:n..px;}  

And to increment that classes and value, for example, until value is 100px. I have this less but I don't want to multiply for every css property:

@iterations: 30;
.loopingClass (@index) when (@index > 0) {
  .classx@{index} { /*classx the class to add in html*/
    margin: ~"@{index}px"; 
  }
  .loopingClass(@index - 1);
}
.loopingClass (0) {}
.loopingClass (@iterations); 

ty.