Answer

Within commonly accepted Jain tradition, I am not aware of any Tirthankar named Bhagwan Vajrasen in the past Chovisis.

Explanation

In Jain tradition, a Chovisi means a group of 24 Tirthankars. Jain texts and traditions describe:

• Past Chovisi — the 24 Tirthankars of the previous time-cycle
• Present Chovisi — the 24 Tirthankars of the current time-cycle, including Bhagwan Rishabhdev to Bhagwan Mahavir
• Future Chovisi — the 24 Tirthankars of the coming time-cycle

Names such as Vajranabha or other “Vajra”-related names may appear in Jain narratives in different contexts, but Vajrasen as a Tirthankar of a past Chovisi is not a standard or widely established name in the accepted lists.

Spiritual Understanding

In Jain Dharma, the names of Tirthankars are sacred and traditionally preserved. Therefore, it is important not to accept a name as a Tirthankar unless it is clearly supported by accepted Jain tradition.

Takeaway

So, respectfully: No, Bhagwan Vajrasen is not known as a Tirthankar in the accepted past Chovisis of Jain tradition.