I'm trying to devise a point system for a project I'm working on and I need to come up with an equation that fits these parameters so that I can fill in the rest of the points. Hopefully someone can help me out. It looks like it should be easy but I can't figure it out. *this is not a school project*

# | points

----------

1 | 1

2 |

3 |

4 |

5 |

6 |

7 |

8 | 0

9 |

10| -1

11| -1

12| -1

13| -1

etc.|etc.