123321

Appears in sequences

• Concatenation of sequence (1, 2, ..., floor((n-1)/2), floor(n/2), floor(n/2)-1, ..., 1) for n >= 1.at n=5A007907
• All possible products in increasing order of two distinct members of the unary sequence 1, 11, 111, 1111, 11111, ...given by A000042.at n=8A077488
• Palindromes formed from the concatenation of n, sum of n and R(n), and R(n) with its leading zeros; or 0 if no such palindrome exists. R(k) is the digit reversal of k.at n=11A084998
• Numbers k that are divisors of the number formed by concatenating (k-1), k and (k+1), in that order.at n=38A088877
• List of molecules in Hintze-Adami artificial chemistry (see comments for definition).at n=22A101145
• a(n) = corresponding product of parts in A110380.at n=7A110381
• Elements of the Motzkin words sub-operad Motz of TN generated by 00 and 010.at n=37A231872
• Concatenation of the numbers from 1 to n with numbers from n down to 1.at n=2A259937
• The concatenation of 123456...n and the reverse of this number.at n=2A261138
• Pseudoprimes to base 6, written in base 6.at n=30A262103
• Breadth-first traversal of a binary tree in which the value at the n-th node is equal to ParentNode()*prime(n-1).at n=26A268878
• Multiplication of pair of contiguous repunits, i.e., (0*1, 1*11, 11*111, 111*1111, 1111*11111, ...).at n=3A274766
• Numbers which are products of repunits.at n=14A308365
• Sum of multinomials M(n-k; p_1-1, ..., p_k-1), where p = (p_1, ..., p_k) ranges over all partitions of n into distinct parts (k is a partition length).at n=15A326493
• Numbers that can be written as a product of distinct repunits.at n=10A334131