111212

Appears in sequences

• List of Lyndon words on {1,2} sorted first by length and then lexicographically.at n=16A102659
• Sorted list of strings that can be obtained by starting with 12 and repeatedly doubling any substring in place.at n=17A130838
• 6-digit numbers k such that: (a) the digits of k are from the set {1, 2, 3, 4, 5}, and (b) any digit that appears in k appears at least twice.at n=5A171725
• Numbers with digital product = 4.at n=38A199987
• Composite numbers whose product of digits is 4.at n=31A201016
• Smallest (i.e., rightmost) Lyndon word in the Lyndon factorization of the binary representation of n (written using 1's and 2's rather than 0's and 1's, since numbers > 0 in the OEIS cannot begin with 0).at n=69A211096
• Largest (i.e., leftmost) Lyndon word in Lyndon factorization of binary vectors of lengths 1, 2, 3, ... (written using 1's and 2's rather than 0's and 1's, since numbers > 0 in the OEIS cannot begin with 0).at n=67A211099
• List of prefix-normal words over the alphabet {1,2}.at n=37A238109
• Positive numbers n such that (digitsum(n))^2 equals (product of digits(n))^3.at n=7A261778
• List of words of length n over an alphabet of size 9 that are in standard order and which have the property that every letter that appears in the word is repeated.at n=19A273978
• Underline all even terms; concatenations of underlined terms and of non-underlined terms both equal the concatenation of the entire sequence. This is the lexicographically earliest such sequence without duplicate terms and with an even digit among the first two terms.at n=14A307312
• The Wythoff representation of n: an alternative way of presenting A189921.at n=27A317208
• a(1) = 1; a(2) = 2; for n > 2, a(n) is the least number > a(n-1) whose decimal representation is uniquely the concatenation of the decimal representations of two distinct earlier terms.at n=30A336528