[3 / 1 / ?]

nth number of this sequence

No.1024136 ViewReplyOriginalReport
1000 2250 3750 5500 7500
+1250 +1500 +1750 +2000
The number that gets added is increased by 250 with each.
Could someone please tell me the equation. THis shouldn't be so fucking difficult for me i did it before but for some reason i just can't