Not Seasonally Adjusted.

What _I think_ they are doing is auctioning Treasury notes.
They offer $50 billion of notes at a very low interest rate and then bid (auction) up the interest rate on the note to see when some bank will bite and lend them money by purchasing a note.

At some point the banks decide the interest rate Fed is offering is high enough that they want to invest in it and they buy the note.

Think of Fed as a homebuyer in an auction house full of mortgage brokers offering to sign a home loan for first 2.0%, then when that fails, 2.1%, and so on. Eventually one of the brokers puts up his hand. Currently the banks have no money to lend because of the securitisation disaster, so interest rates on the notes have to be high and Fed must print lots of money each month to make payments. So yes, pumping the economy by pouring money into banks, off into the future. Banks are getting a nice ROI for investing in .. nothing.