Based on the given feature description, it appears that the SEQN feature represents a respondent sequence number. Without any further information or domain knowledge, it is difficult to determine an appropriate range of values for the SEQN feature. However, we can assume that each respondent would have a unique sequence number.

To generate the requested dictionary, I will create two lists of typical SEQN values for each target class, 'Adult' and 'Senior'. Since the feature description does not specify any ranges or criteria for different age groups, I will randomly select SEQN values for each category.

```json
{
	"Adult": [10101.0, 20562.0, 30923.0, 41384.0, 51845.0],
	"Senior": [60101.0, 70562.0, 80923.0, 91384.0, 101845.0]
}
```