131211

Appears in sequences

• Concatenation of the numbers of equal successive digits of previous two terms read in inverse order, starting with a(1)=a(2)=1.at n=10A113721
• Numbers whose decimal expansion is a concatenation of 3 consecutive decreasing numbers.at n=11A127424
• Twin prime pairs concatenated to their average in decimal representation (the greater twin prepended, the lesser appended).at n=2A268146
• Similar to the "Look and Say" sequence, with the added requirement that every third digit describes the location of a digit in blocks of three in the previous term.at n=3A349951