The sum of the first 2005 terms of the sequence 1,2,3,4,1,2,3,4,… is
(A) 5011 (B) 5110 (C) 5020 (D) 5010 (E) 501
Want a route through all this instead of an archive?
The track
puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.