# Pure recurrence relation for partition function

The following formula holds: $$p(n)=\displaystyle\sum_{1 \leq \frac{3k^3 \pm k}{2} \leq n} (-1)^{k-1} p \left( n - \dfrac{3k^2 \pm k}{2} \right),$$ where $p(n)$ denotes the partition function and $\sigma_1$ denotes the sum of divisors function.