A357118 - OEIS

%I #42 Nov 12 2022 01:36:44

%S 322,323,4222,4224,4242,4244,4300,4303,4304,4311,4313,4314,4322,4323,

%T 4324,4330,4331,4332,4335,4336,4337,4338,4339,4340,4341,4342,4345,

%U 4346,4347,4348,4349,4353,4354,4355,4363,4364,4366,4373,4374,4377,4383,4384,4388,4393,4394,4399

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

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

%C The sequence is finite. The last term is 989765432.

%C There are 11041830 terms. - _Michael S. Branicky_, Oct 20 2022

%H Michael S. Branicky, <a href="/A357118/b357118.txt">Table of n, a(n) for n = 1..10000</a>

%e 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.

%o (Python)

%o def ok(n):

%o     s = str(n)

%o     if len(s) < 2 or len(s) > 9: return False

%o     return len(s) == int(s[0]) and len(set(s)) == int(s[1])

%o print([k for k in range(4394) if ok(k)]) # _Michael S. Branicky_, Oct 17 2022

%Y Cf. A319678.

%K nonn,base,fini

%O 1,1

%A _Marc Morgenegg_, Oct 17 2022