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A209929 Smallest digit of all divisors of n. 4
1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1

COMMENTS

Also smallest digit of concatenation of all divisors  of n (A037278, A176558).

Also characteristic function of numbers n such that smallest digit among all divisors of n is 1 (A209931), in other words, numbers whose divisor set does not contain any number with a nonleading zero.

Sequence is not the same as A168184, first deviation is at a(101): A168184(101) = 1, a(101) = 0.

Sequence is not the same as A168046, first deviation is at a(214): A168046(214) = 1, a(214) = 0.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for characteristic functions

EXAMPLE

a(214) = 0 because smallest digit of all divisors of 214 (1, 2, 107, 214) is 0.

MATHEMATICA

Table[Min[Flatten[IntegerDigits/@Divisors[n]]], {n, 100}] (* Harvey P. Dale, Jul 20 2015 *)

PROG

(PARI)

A168046(n) = if(!n, 0, !!(vecsort(digits(n), , 8)[1]));

A209929(n) = { my(divs=divisors(n)); factorback(vector(numdiv(n), i, A168046(divs[i]))); }; \\ Antti Karttunen, Dec 07 2017

CROSSREFS

Cf. A168046, A209928 (largest digit of all divisors of n), A054054 (smallest digit of n).

Sequence in context: A279693 A054527 A137794 * A105586 A202022 A136522

Adjacent sequences:  A209926 A209927 A209928 * A209930 A209931 A209932

KEYWORD

nonn,base,less

AUTHOR

Jaroslav Krizek, Mar 20 2012

EXTENSIONS

More terms from Antti Karttunen, Dec 07 2017

STATUS

approved

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Last modified April 23 07:51 EDT 2019. Contains 322381 sequences. (Running on oeis4.)