Which will come next in the following series?
B2E, D5H, F12K, H27N, ?

Let's break down the alphanumeric series into three individual patterns:
1. First Letter: B (+2) $\to$ D (+2) $\to$ F (+2) $\to$ H (+2) $\to$ J
2. Middle Number: The sequence follows the recursive rule ${\text{Term}}_n=({\text{Term}}_{n-1}\times 2)+(n-1)$ where $n$ is the step position:

* $2\times 2+1=5$
* $5\times 2+2=12$
* $12\times 2+3=27$
* $27\times 2+4=58$

3. Last Letter: E (+3) $\to$ H (+3) $\to$ K (+3) $\to$ N (+3) $\to$ Q

Combining these three outputs gives J58Q.