Let L be a connected finite type graded Lie algebra. If dim L = infinity and gldimL < infinity, then log index L = alpha > 0. If, moreover, alpha < infinity, then for some Sigma(d-1)(i=1) dim Lk+i = e(k alpha k), where alpha(k) -> log index L as k -> infinity.
Félix, Y., Halperin, S., & Thomas, J.-C. (2007). Exponential growth of lie algebras of finite global dimension. Proceedings of the American Mathematical Society, 135(5), 1575-1578. https://doi.org/10.1090/S0002-9939-07-08721-7 (Original work published 2007)