login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A285271 Numbers that are divisible by each of their digits but that are not divisible by the sum of their digits or by the product of their digits. 2

%I #62 Mar 11 2021 20:44:38

%S 11,15,22,33,44,48,55,66,77,88,99,115,122,124,126,128,155,162,168,175,

%T 184,212,222,244,248,264,288,324,333,336,366,384,396,412,424,444,448,

%U 488,515,555,636,648,666,672,728,777,784,816,824,848,864,888,936,999,1111,1112

%N Numbers that are divisible by each of their digits but that are not divisible by the sum of their digits or by the product of their digits.

%C Numbers which are divisible by the sum and the product of their digits (A038186) are also divisible by each of their digits (A034838)

%C The product of the digits of n are trivially divisible by each digit; so if that product divides n, each digit must divide n. - _Franklin T. Adams-Watters_, Jul 02 2017

%H Robert G. Wilson v, <a href="/A285271/b285271.txt">Table of n, a(n) for n = 1..1520</a>

%e 15 is divisible by its digits 1 and 5, and 15 is divisible by the product of its digits 1*5 = 5, but 15 is not divisible by the sum of its digits 1+5 = 6, hence 15 is a term.

%e 48 is divisible by its digits 4 and 8, and 48 is divisible by the sum of its digits 4+8 = 12, but 48 is not divisible by the product of its digits 4*8 = 32, hence 48 is a term.

%e 124 is divisible by its digits 1, 2 and 4, but 124 is not divisible by the product of its digits 1*2*4 = 8 and 124 is not divisible by the sum of its digits 1+2+4 = 7, hence 124 is a term.

%e 24 is divisible by its digits 2 and 4, and 24 is divisible by the sum of its digits 2+4 = 6, and 24 is also divisible by the product of its digits 2*4 = 8, hence 24 is NOT a term.

%p filter:= proc(n) local F;

%p F:= convert(n,base,10);

%p andmap(t -> t > 0 and n mod t = 0, F) and not(n mod convert(F,`+`) = 0 and n mod convert(F,`*`) = 0)

%p end proc:

%p select(filter, [$11 .. 2000]); # _Robert Israel_, Jul 05 2017

%t fQ[n_] := Block[{ind = IntegerDigits@ n}, Union[ IntegerQ@# & /@ (n/ind)] == {True} && (!IntegerQ[n/Plus @@ ind] || !IntegerQ[n/Times @@ ind])]; Select[Range@ 1112, fQ] (* _Robert G. Wilson v_, Jul 05 2017 *)

%o (PARI) isok(n) = {d = digits(n); if (vecmin(d), for (k=1, #d, if (n % d[k], return (0));); return ((n % vecsum(d)) || (n % prod(k=1, #d, d[k])));); return (0);} \\ _Michel Marcus_, Jul 02 2017

%Y Subsequence of A034838.

%Y Cf. A005349, A007602, A038186.

%K nonn,base

%O 1,1

%A _Bernard Schott_, Jun 24 2017

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 24 06:39 EDT 2024. Contains 371920 sequences. (Running on oeis4.)