Question 90053
3, 7, 11, 15, _____________

The difference between the numbers is exactly 4.
3+4=7, 7+4=11, 11+4=15, 15+4=19, 19+4=23, etc___________________



1, -2, 4, -8 ________________
1-3=-2, -2 +(-3*-2=-6)=4, 4+(-6*2=-12)=-8, -8+(-12*-2=24)=16, etc...