Base 21 has 12 possible final digits
At 1 digits, there were 8 primes, 0 leaders
At 2 digits, there were 32 primes, 0 leaders
At 3 digits, there were 86 primes, 8 leaders
At 4 digits, there were 166 primes, 24 leaders
At 5 digits, there were 259 primes, 70 leaders
At 6 digits, there were 313 primes, 85 leaders
At 7 digits, there were 343 primes, 132 leaders
At 8 digits, there were 307 primes, 123 leaders
At 9 digits, there were 254 primes, 110 leaders
At 10 digits, there were 199 primes, 98 leaders
At 11 digits, there were 122 primes, 54 leaders
At 12 digits, there were 82 primes, 37 leaders
At 13 digits, there were 54 primes, 35 leaders
At 14 digits, there were 20 primes, 13 leaders
At 15 digits, there were 11 primes, 7 leaders
At 16 digits, there were 7 primes, 4 leaders
At 17 digits, there were 5 primes, 3 leaders
At 18 digits, there were 3 primes, 3 leaders
In total, in base 21 there were 2271 primes and 806 leaders, maxlen=18