Quadratic sequences

1

What's the second difference in this sequence: {4},~{7},~{12},~{19},~{...}

2

What's the second difference in this sequence: {3},~{7},~{13},~{21},~{...}?

3

If the second difference is {2}, the {n}^{th} term is certain to include the term:

4

What's the next term in this quadratic sequence: {4},~{7},~{12},~{19},~{...}?

5

What's the next term in this quadratic sequence: {6},~{9},~{14},~{21},~{...}?

6

What's the second difference in this sequence: {4},~{7},~{14},~{25},~{...}?

7

What's the {n}^{th} term for the sequence {4},~{7},~{12},~{19},~{...}?

8

What's the {n}^{th} term for the sequence {7},~{13},~{23},~{37},~{...}?

9

What's the {n}^{th} term in this quadratic sequence: {6},~{9},~{14},~{21},~{...}?

10

What's the {n}^{th} term in this sequence: {-1},~{5},~{15},~{29},~{...}?