Available just about 18-19% of all 5N.co (w/o 4,0)
here some nice ones:
ABACB, ABCAC patterns:
13515.co
13616.co
13717.co
13919.co
15125.co
15135.co
15165.co
15175.co
15195.co
15212.co
15313.co
15616.co
15717.co
15919.co
16126.co
16136.co
16156.co
16196.co
16212.co
16313.co
16515.co
16717.co...