@tomleslie 

Got it. Thanks!

@Kitonum 

Thanks for your answer and clear example. It would be nice if you can help me with this code to see the sequence list starting at point 1.

In addition,
- All the 50 vertices has a value, located in a list L. 
- When a vertex connects to another vertex it should add the value of the vertex (located in list L) to a ''sum'' list X . When the sum of the values (list X) is greater than 500, it should stop adding more vertices to the sequence list. At the end not all the 50 vertices are part of the minimal spanning tree. 

It would be great if you can help me with the code!

Thanks