# Homework problem on identifying a sequence

I had this problem in my discrete math/modular arithmatic course where I had to find the first 10 terms of a series F(r), starting from F(3).

The given information is:

F(3)=1
F(4)=13
F(10) % (10^9+7) is 719666144
F(r) is defined and exists for all values of r>=3

Is it possible to solve such problems? How do we approach these? Is there anyway we can actually find the general term?

EDIT: One of my friends claimed he solved the complete problem fron this much data. I just wanted to check If there is someone that bright actually present or that he was just bragging.

We define an onto function from $[n] \times [n]$ to $[n-2] \cup \{0\}$ as follows, where $[n] = \{1,2,3,\ldots ,n\}$,

$$f : [n] \times [n] \rightarrow [n-2] \cup \{0\}.$$

1) $f(x,x) = 0$.

2) $f(x,y) = f(y,x) > 0$, for $y ≠ x$.

3) $f(x,y) \leq \max\{f(x,z),f(z,y)\}$ for all $x,y,z$ belonging to $[n]$.

F(r) is the number of ways in which f(x,y) can be defined for n=r.

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What's stopping you from setting $F(r) = 0$, $r \ne 3,4,10$? There have to be more conditions? –  Cocopuffs Jun 12 '13 at 19:09
We just saw this one here where it was closed as not a real question. –  Ross Millikan Jun 12 '13 at 19:12
Based on my mind-reading skills, I believe this might be the actual problem. –  Peter Košinár Jun 12 '13 at 19:14
@PeterKošinár Great find! –  Cocopuffs Jun 12 '13 at 19:16
I request the administrator to kindly block/delete this question as this is from a contest on a programming site which is still going on.codechef.com/JUNE13/problems/SPMATRIX here is the link.Thankyou. –  swapedoc Jun 12 '13 at 21:07