printf("%s.com/%d", x, y);

author: Nic Bricknell

The string "1505132614411800" could be broken into strings of four characters each, resulting the following founding years of Cambridge colleges:

• 1505: Christ's
• 1326: Clare
• 1441: King's
• 1800: Downing

From these we get X (cross from "Christs"), C (from Clare), K (from King's), and D (from Downing), giving us XCKD.

The string then is clearly "xkcd", and the number is the permutation performed on "xckd" to get "xkcd", i.e., 1324. The solution is the title of the xkcd comic numbered 1324: weather.