secuencia de números

2 , ____________________ , 6 , ____________________ , 10 , ____________________ , 14 , ____________________ , 18 , ____________________
____________________ , 6 , ____________________ , 12 , ____________________ , 18 , ____________________ , 24 , ____________________ , 30 .
4 , ____________________ , 12 , ____________________ , 20 , ____________________ , 28 , ____________________ , 36 , ____________________ .
____________________ , 10 , ____________________ , 20 , ____________________ , 30 , ____________________ , 40 , ____________________ , ____________________