Increment by 4

I have an issue with excel that I need to increment by 4. For example column A is numbered 1000 to 2999. I need column B to go down the rows but with an incrementation of every 4th row.
For example:

Column B rows 1 through 4 will be 1000, rows 5 through 8 will be 1001, rows 9-12 will 1002 and so on until I reach 1499. I'm can't program but if there were some steps to make this happen I would appreciate it.