Auto incrementing every second row in ArcGIS Desktop?

Question

How do I auto increment every second row (field type is short and I work with 150 fields) in ArcGIS Desktop 10.3.1?

I saw this code in https://support.esri.com/en/technical-article/000011137

rec=0 
def autoIncrement(): 
 global rec 
 pStart = 1  
 pInterval = 1 
 if (rec == 0):  
  rec = pStart  
 else:  
  rec += pInterval  
 return rec

 autoIncrement()

and the unwanted result is the blue arrow, whereas i need the result will be the as the yellow arrow (i changed it manually):

Answer 1

Not tested, but this should work:

rec=0 
action = 'jump'
def autoIncrement(): 
 global rec
 global action  
 pStart = 1  
 pInterval = 1 
 if (rec == 0):  
  rec = pStart
  return rec
 else:
  if action == 'count':
   rec += pInterval
   action = 'jump'
   return rec
  elif action == 'jump':  
   action = 'count'
   return 0

 autoIncrement()