1222221

Appears in sequences

• k th digit of a(n) is the number of different digits within 3 of k (not including k).at n=26A039989
• k th digit of a(n) is the number of different digits within 4 of k (not including k).at n=24A039990
• All possible products in increasing order of two distinct members of the unary sequence 1, 11, 111, 1111, 11111, ...given by A000042.at n=10A077488
• Numbers n such that the set S(n) = {k: k + reverse(k) = n} is not empty, at least one element of S(n) has the same number of digits as n and at least one element of S(n) has one digit less than n has.at n=12A088171
• Expansion of g.f. x*(1+10*x)/((1-x)*(1-10*x^2)).at n=12A094623
• Expansion of g.f. x*(1+11*x+x^2)/((1-x)*(1+x)*(1-10*x^2)).at n=12A094624
• List of molecules in Hintze-Adami artificial chemistry (see comments for definition).at n=32A101145
• a(n) = n 2's sandwiched between two 1's.at n=5A132583
• a(n) = 111111*n.at n=10A154549
• List of privileged words over the alphabet {1,2}.at n=35A235609
• Palindromes p = A002113(n) whose index n is a substring of p.at n=22A248753
• Palindromes p=A002113(n) whose index n is also a palindrome and in addition a substring of p (strings in base 10).at n=11A248754
• Numbers which are products of repunits.at n=20A308365
• Numbers that can be written as a product of distinct repunits.at n=12A334131
• a(1) = 1; for n > 1, a(n) is the smallest unused positive number such that a(n), |a(n) - a(n-1)| and a(1) + ... +a(n) are all palindromes.at n=28A376856