Based on your query, I would recommend using RockettAI for creating a detailed lesson plan on the math topic of determining arithmetic means and the nth term of an arithmetic sequence.

RockettAI is an AI-powered platform that offers a comprehensive range of tools for teachers, including a Lesson Planning feature that can streamline the process of creating detailed lesson plans. This feature can be particularly useful for your specific need of planning a math lesson on arithmetic sequences.

Additionally, RockettAI also offers a Repetitive Maths Practice tool. This feature provides interactive and adaptive practice exercises that can reinforce essential math concepts. It can be used to create practice exercises on arithmetic means and nth term of an arithmetic sequence, allowing students to apply what they've learned in the lesson.

Lastly, the Activity Generator in RockettAI can provide engaging activities related to the topic, which can further enhance the learning experience for your students.

In summary, RockettAI can be a powerful tool in planning and executing your math lesson effectively.