1211221

Appears in sequences

• Numbers that eventually reach 1 under "x -> sum of 5th power of digits of x".at n=19A219112
• The word 1 belongs to the sequence, and whenever a word w belongs to the sequence, then the words consisting of 1's and 2's whose run lengths transform equals w also belong to the sequence.at n=31A376637
• Smallest number with a n-character traditional Japanese notation.at n=11A384792