What row of numbers comes next? (This is a tough one!)

• 1
• 11
• 21
• 1211
• 111221
• 312211
• 13112221

(From - http://www.riddlenut.com/)

1113213211

Starting with the first line "1", every following line describes (using pairs of digits) the line above it:
Second line reads:
11 = "One 1" (1)
Third line reads:
21 = "Two 1's" (11)
Fourth line reads:
12,11 = "One 2, One 1" (21)
Fifth line reads:
11,12,21 = "One 1, One 2, Two 1's" (1211)
etc.

Posted by Nick Reed on 2002-11-12 03:12:05