What about thirty-seven?

[mkapstei at UCHICAGO.EDU]

The late Alex Wayman once wrote a piece in 
which he sought to explain the 37 Buddhas of
the Mahaayaana rite of contrition as an originally 
astral grouping. I am sorry that I do not have the
precise reference at hand just now, but it's in one 
of his volumes on the tantras.

Matthew T. Kapstein
Numata Visiting Professor of Buddhist Studies
The University of Chicago Divinity School
Directeur d'études
Ecole Pratique des Hautes Etudes, Paris