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A245680 Numbers x whose digits can be permuted to produce a multiple of x. 3

%I #33 Nov 02 2015 10:22:36

%S 1035,1089,1359,1386,1782,2178,2475,10035,10089,10350,10449,10890,

%T 10899,10989,11688,11883,12375,12903,13029,13359,13449,13590,13599,

%U 13659,13860,13986,14085,14247,14724,14859,15192,16782,17604,17802,17820,17832,17982,18027

%N Numbers x whose digits can be permuted to produce a multiple of x.

%C A008919 is a subset of this sequence.

%C Every element of the sequence is divisible by 3. - _Emmanuel Vantieghem_, Oct 27 2015

%C It is an obvious fact that if a(n) is the n-th term of the sequence, then a(n)*(10^k) is also a member of the sequence for all k > 0. - _Altug Alkan_, Nov 01 2015

%H Paolo P. Lava, <a href="/A245680/b245680.txt">Table of n, a(n) for n = 1..100</a>

%e A permutation of 1782 is 7128 and 7128 / 1782 = 4.

%e A permutation of 11688 is 81816 and 81816 / 11688 = 7.

%p P:=proc(q) local a, b, c, i, j, k, n, t; for n from 1 to q do a:=n; b:=[];

%p while a>0 do b:=[a mod 10, op(b)]; a:=trunc(a/10); od;

%p t:=0; for i from 2 to 9 do a:=i*n; c:=[];

%p while a>0 do c:=[a mod 10, op(c)]; a:=trunc(a/10); od;

%p if sort(b)=sort(c) then print(n); break; fi; od; od; end: P(10^6);

%p # Alternative:

%p N:= 100: # to get the first N entries

%p count:= 0:

%p for x from 10 while count < N do

%p M:= 10^(ilog10(x)+1)-1;

%p L:= sort(convert(x,base,10));

%p for i from 2 to floor(M/x) do

%p Lp:= sort(convert(i*x,base,10));

%p if Lp = L then

%p count:= count+1;

%p A[count]:= x;

%p break;

%p fi

%p od

%p od:

%p seq(A[i],i=1..count); # _Robert Israel_, Jul 29 2014

%t fQ[n_] := AnyTrue[Rest[FromDigits /@ Permutations[IntegerDigits@ n]], Divisible[#, n] &]; Select[Range@ 20000, fQ] (* _Michael De Vlieger_, Oct 27 2015, Version 10 *)

%o (Python)

%o import itertools

%o from itertools import permutations

%o for n in range(1,10**5):

%o ..plist = list(permutations(str(n)))

%o ..for i in plist:

%o ....num = ''

%o ....for j in range(len(i)):

%o ......num += i[j]

%o ....if int(num)%n==0 and int(num)/n > 1:

%o ......print(n,end=', ') # _Derek Orr_, Jul 29 2014

%o (PARI)

%o for(n=1,10^8,d=vecsort(digits(n));p=0;for(k=2,9,dd=vecsort(digits(n*k));if(d==dd,p++;break));if(p>0,print1(n,", "))) \\ quicker program _Derek Orr_, Jul 29 2014

%Y Cf. A008919, A096092, A096093, A245682.

%K nonn,base

%O 1,1

%A _Paolo P. Lava_, Jul 29 2014

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Last modified April 24 04:14 EDT 2024. Contains 371918 sequences. (Running on oeis4.)