I am wondering if there is a recurrent formula to calculate the eigenvalues of the Laplacian for the Sierpinski gasket of any generation. Does anybody know about it? Thanks a lot in advance.
Dirichlet or Neumann boundary condition? Anyway, both cases are treated in this paper by Teplyaev. If it does not quite answer your question, you can ask the author directly. The email given in the paper is old, he's now at UConn.