1000021

Appears in sequences

• Lexicographically earliest strictly increasing base 5 autovarious sequence: a(n) = number of distinct a(k) mod 5^n (written in base 5).at n=30A038114
• Lexicographically earliest strictly increasing base 6 autovarious sequence: a(n) = number of distinct a(k) mod 6^n (written in base 6).at n=23A038115
• Smallest n-digit squarefree number whose internal as well as external digits form a squarefree number greater than 1; or 0 if no such number exists.at n=6A077379
• Where records occur in A119451.at n=27A119453
• Semiprimes with sum of digits 4.at n=25A382073