Number-sequence puzzle

Question

Here's a number sequence puzzle on INSC-2017:

132, 2646, 2128128, ?, 8482124821221022.5

I managed to get some progress but don't know how to complete it (progress deleted as comment request).

Answer 1

Although there is an aberration in the pattern, I believe the number is

42416241615.

The pattern is then

132, 2646, 2128128, 42416241615, 8482124821221022.5

Reasoning:

You have to double each number in the previous term and concatenate them. Then calculate the sum of all the digits in the current term and divide it by 2, and concatenate that number to the end.

Namely:

$2*2||1*2||2*2||8*2||1*2||2*2||8*2|| = 424162416$. Then $\frac{4+2+4+1+6+2+4+1+6}{2} = \frac{30}{2} = 15$, so the term is 42416241615. If we take this number, then $4*2||2*2||4*2||1*2||6*2||2*2||4*2||1*2||6*2||1*2||5*2|| = 84821248212210$. Then $\frac{8+4+8+2+1+2+4+8+2+1+2+2+1+0}{2} = \frac{45}{2} = 22.5$, so the term is 8482124821221022.5.

This works except for

the random 2 which starts 2128128, which should be a 4 (that term should instead be 4128129, then the next term ought to be 82416241818, and following that 16482124821621622.