InterviewBit Problems   Intersecting Chords in a Circle : Unsolved

About the Intersecting Chords in a Circle : Unsolved category (1)
Please explain test case 3 (2)
Nasty overflow problem (1)
I am not able to understand recursion relationship (5)
Can anyone please help me?Whats wrong in this code?I am getting a different ans for n>21 (2)
Unclear explanation of problem (1)
There is a good reason this question has not been asked in any company (1)
This recursion relation is not easy to digest (1)
What should be the answer for A=3? Should it be 3 or 5? (3)
What is a chord? (2)
Why it is giving wrong ans after 20 (2)
Wrong answer for 22? (2)
What does using 2*N points mean? (2)
Why to take modulus with 1e+7 (2)
Make sure to put modulo of 1000000007 (1)