What's the sequence number in the following proble,
1236, 1352,? 1590

Note that the difference between the first two numbers is 116, and between the second and fourth numbers is 238, which 118 + 120. See a pattern?

The pattern is
1236 , 1352, 1590
12 12*3, 13 13*4 , 14 14*5 , 15 15*6
1236, 1352,1470,1590
So the missing number is 1470