I find it hard to believe there were any 41 story buildings in Washington DC.
This inquiry was made a year or so ago was it not? try searching the the forum. Dan-San answered the inquiry then as well.
Most of all the tall building nowadays are in Arlington, VA across the river. The tallest building is the Washington monument which is not a building at all it stands at 555' approx.
The tallest residential building in DC was the Cairo which was built before 1900.
and for some architectural history read
http://www.metroweekly.com/feature/?ak=295