Create sequential numbers in a field using Python in the Field Calculator

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  1. Create a new short integer field.
  2. Set the Parser to Python.
  3. Select Show Codeblock.
  4. Paste the following into the Pre-Logic Script Code: 
rec=0
def autoIncrement():
global rec
pStart = 1
pInterval = 1
if (rec == 0):
rec = pStart
else:
rec += pInterval
return rec
5. Paste the following code in the smaller box below the Pre-Logic Script Code: 

autoIncrement()
6. Click OK.

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