A209930 - OEIS

A209930

Numbers n such that largest digit of all divisors of n is 1.

1, 11, 101, 1111, 10111, 101111, 1011001, 1100101, 10010101, 10011101, 10100011, 10101101, 10110011, 10111001, 11000111, 11100101, 11110111, 11111101, 100100111, 100111001, 101001001, 101001011, 101100011, 101101111, 101111011, 101111111, 110010101

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OFFSET

1,2

COMMENTS

Also numbers n such that largest digit of concatenation of all divisors (A037278) of n is 1.

What is the smallest n with a(n) <> A203304(n)? - Alois P. Heinz, Jul 16 2014

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..8503

EXAMPLE

Number 1111 is in sequence because largest digit of all divisors of 1111 (1, 11, 101, 1111) is 1.

MATHEMATICA

t = {}; n = 0; While[Length[t] < 30, n++; m = FromDigits[IntegerDigits[n, 2]]; If[Max[Union[Flatten[IntegerDigits[Divisors[m]]]]] <= 1, AppendTo[t, m]]]; t (* T. D. Noe, Jan 30 2013 *)

CROSSREFS

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

Cf. A203304.

Sequence in context: A006943 A073030 A290295 * A203304 A283906 A284028

Adjacent sequences: A209927 A209928 A209929 * A209931 A209932 A209933

KEYWORD

nonn,base

AUTHOR

Jaroslav Krizek, Mar 20 2012

EXTENSIONS

Corrected by Jaroslav Krizek, Jan 29 2013

STATUS

approved