TITLE: Faithful projective representations of symmetric groups
QUESTION [8 upvotes]: This is a reference request.
Do you know where I can find the dimensions of the faithful projective representations of $S_n$ and $A_n$ for $n\ge 5$?
Thank you in advance.

REPLY [11 votes]: Maybe it's worth adding a reference to a modern treatment of Schur's work in book form, which might be easier to read than the original paper of Schur (note that I'm unrelated to the authors):
P.N. Hoffman and J.F. Humphreys, Projective representations of the symmetric groups.
Q-functions and shifted tableaux.
Oxford Mathematical Monographs.
Oxford Science Publications.
The Clarendon Press, Oxford University Press, New York, 1992.

REPLY [8 votes]: See Schur's original paper
Schur, I. (1911), Über die Darstellung der symmetrischen und der 
alternierenden Gruppe durch gebrochene lineare Substitutionen,
Crelle's Journal 139: 155–250. (EuDML)