Posted by Karinna on Tuesday, March 20, 2012 at 8:14pm.
input:1 output:4
input:2 output:7
input:3 output:10
input:4 output:13
What is the rule?

math  Anonymous, Tuesday, March 20, 2012 at 8:45pm
the rule is x3+1

math  ahem  Steve, Wednesday, March 21, 2012 at 12:22pm
Looks more like 3x+1
technically, since multiplication is commutative, x3 is the same as 3x, but you will find most people put the numeric coefficient first. . . 
math  Anonymous, Sunday, September 30, 2012 at 2:33pm
53
16564
21641
60
3
140.
2548