10000021

Appears in sequences

• Lexicographically earliest strictly increasing base 7 autovarious sequence: a(n) = number of distinct a(k) mod 7^n (written in base 7).at n=27A038116
• Lexicographically earliest strictly increasing base 8 autovarious sequence: a(n) = number of distinct a(k) mod 8^n (written in base 8).at n=30A038117
• Lexicographically earliest strictly increasing base 9 autovarious sequence: a(n) = number of distinct a(k) mod 9^n (written in base 9).at n=33A038118
• 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=7A077379
• Numbers k such that there are 15 digits in k^2 and for each factor f of 15 (1,3,5) the sum of digit groupings of size f is a square.at n=11A153751
• a(n) = Sum_{d|n} n^(d').at n=9A348280
• Semiprimes with sum of digits 4.at n=34A382073