I am trying to find the optimal solution for the following linear integer programming:
\begin{eqnarray} &&\underset{x_i, \forall i} {\text{maximize}} ~ \sum_{i=1}^N x_i a_i \\ && \text{s.t.} \sum_{i=1}^N i ~x_i \leq B, ~~~x_i \in \mathbb N_{0}, ~\forall i. \nonumber \end{eqnarray}
where $a_i$'s are known positive coefficients.