Question 54
Denote by $d(a, b)$ the number of the divisors of a positive integer $a$, which are greater than or equal to $b$. Find all positive integers $n$ such that
$$
d(3 n+1,1)+d(3 n+2,2)+\cdots+d(4 n, n)=2006
$$
$$
d(3 n+1,1)+d(3 n+2,2)+\cdots+d(4 n, n)=2006
$$