Simple 1NT sequences: 

1Maj-1NT
2X- 	-2Maj	0-9 with simple preference to major 
	-2Y	long suit, weak hand (about 6-9)
	-2NT	10-11 balanced
	-3Y	long suit, good hand (10-11) 
	-3Maj	10-11 with balanced 3 card raise