A221698 Composite numbers n such that largest digit of all divisors of n is 2.

22, 121, 202, 1111, 2222, 10201, 12221, 20222, 22121, 111221, 112211, 202222, 220121, 221111, 222211, 1021211, 1112221, 1122011, 1222201, 2021111, 2022002, 2022121, 2121101, 2122111, 2200202, 2202211, 2211121, 2212111, 2222011, 10212211, 11112211, 11121011

Offset: 1

Author

Jaroslav Krizek, Jan 22 2013

Keywords

• nonn
• base

Comments

Also composite numbers n such that largest digit of concatenation of all divisors (A037278) of n is 2.

Composite numbers n such that A209928(n) = 2.

Complement of A106100 with respect to A221697.

Examples

			Number 10201 is in the sequence because the largest digit of all divisors of 10201 (1, 101, 10201) is 2.
		

Crossrefs

Cf. A209928 (largest digit of all divisors of n), A221697.

Programs

Mathematica

t = {}; n = 1; While[Length[t] < 40, n++; m = FromDigits[IntegerDigits[n, 3]]; If[! PrimeQ[m] && Max[Union[Flatten[IntegerDigits[Divisors[m]]]]] <= 2, AppendTo[t, m]]]; t (* T. D. Noe, Jan 30 2013 *)