Command: dagen(dag_maand_jaar)
  
Syntax:
  include datarout.e
  s = dagen(sequence_dag_maand_jaar))
  
Description: 
  Calculate the number of dag from 1-1-1934

Comments: 
  You can do the same from 1-1-1990 as long
  monday is the first day of the year .
  Because monday is seen as the first day of the week .
  (ISO  8601)

Example: 
  s = dagen({1,3,2014})
  gives s is 29280

See Also: 
  datum , week_nummer 
