A357118 Numbers such that the first digit is the number of digits and the second digit is the number of distinct digits.

322, 323, 4222, 4224, 4242, 4244, 4300, 4303, 4304, 4311, 4313, 4314, 4322, 4323, 4324, 4330, 4331, 4332, 4335, 4336, 4337, 4338, 4339, 4340, 4341, 4342, 4345, 4346, 4347, 4348, 4349, 4353, 4354, 4355, 4363, 4364, 4366, 4373, 4374, 4377, 4383, 4384, 4388, 4393, 4394, 4399

Offset: 1

Author

Marc Morgenegg, Oct 17 2022

Keywords

• nonn
• base
• fini

Comments

By definition, each term must be at least a two-digit number.

The sequence is finite. The last term is 989765432.

There are 11041830 terms. - Michael S. Branicky, Oct 20 2022

Examples

			322 is a term because the first digit is the number of digits = 3, and the second digit counts the different digits {2,3} = 2.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A319678.

Programs

Python

def ok(n):
    s = str(n)
    if len(s) < 2 or len(s) > 9: return False
    return len(s) == int(s[0]) and len(set(s)) == int(s[1])
print([k for k in range(4394) if ok(k)]) # Michael S. Branicky, Oct 17 2022