Based on the given feature description and task, it seems that the feature SEQN represents the respondent sequence number. To determine the appropriate ranges of values for different age groups, we need more information about the age groups or the dataset itself. However, we can assume that the respondent sequence number may not directly correspond to the age of the person and may not have a strong relationship with the age group.

Without further information, we cannot determine the typical SEQN values for each age group accurately. However, we can create a dictionary structure with placeholder values for demonstration purposes:

```json
{
    "Adult": [100001.0, 100005.0, 100010.0, 100015.0, 100020.0],
    "Senior": [200001.0, 200005.0, 200010.0, 200015.0, 200020.0]
}
```

Please note that these SEQN values are placeholders and may not represent the actual typical SEQN values for each age group.