111213

Appears in sequences

• Decimal concatenation of n, n+1, and n+2.at n=11A001703
• Concatenate prevprime(n), n, and nextprime(n).at n=9A049857
• a(1) = 1; to form a(n+1), append a(n)-1, a(n)+1 at the beginning and the end of a(n), respectively. Ignore any leading 0's.at n=2A056540
• Concatenate the consecutive increasing numbers starting with prime(n) and ending with prime(n+1).at n=4A111875
• Duplicate of A001703.at n=11A127422
• Twin prime pairs concatenated to their average in decimal representation (with the lesser twin prepended and the greater twin appended).at n=2A268145
• Look and Say the digits of the last three terms, by increasing digit value. Start with a(1)=1, a(2)=2 and a(3)=3.at n=3A300191
• a(n) is the smallest number not occurring earlier whose concatenation with the previous term contains the smallest possible number of numeric substrings strictly larger than for the preceding term; a(0) = 0.at n=23A307511
• Numbers whose digit product equals the number of their digits.at n=25A321771
• Number of tilings of a 20 X n rectangle using 2*n copies of the disconnected shape [ooooo_____ooooo].at n=41A322473