A057303 Numbers n such that the number of distinct digits in n is a digit of n.

1, 11, 12, 20, 21, 23, 24, 25, 26, 27, 28, 29, 32, 42, 52, 62, 72, 82, 92, 103, 111, 112, 121, 122, 123, 130, 132, 134, 135, 136, 137, 138, 139, 143, 153, 163, 173, 183, 193, 200, 202, 203, 211, 212, 213, 220, 221, 223, 224, 225, 226, 227, 228, 229, 230, 231

Offset: 1

Author

Simon Colton (simonco(AT)cs.york.ac.uk), Aug 25 2000

Keywords

• nonn
• base

Comments

The repunits (A000042) are a subsequence. Analogous in construction to the refactorable numbers (A033950).

Examples

			103 has 3 distinct digits in base 10 and 3 is a base 10 digit of 103.
		

References

• S. Colton, Unpublished PhD Thesis, University of Edinburgh, 2000.

Links

• S. Colton, Refactorable Numbers - A Machine Invention, J. Integer Sequences, Vol. 2, 1999, #2.
• S. Colton, HR - Automatic Theory Formation in Pure Mathematics

Crossrefs

Cf. A000042.

Programs

PARI

isok(n) = {my(d = vecsort(digits(n),,8)); vecsearch(d, #d);} \\ Michel Marcus, Feb 23 2016