login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Numbers, not divisible by 10, whose digits can be permuted to get a proper divisor.
4

%I #9 Jun 01 2020 20:47:38

%S 105,108,405,702,703,1001,1005,1008,1053,2002,2016,2025,2079,2106,

%T 3003,3024,3042,3045,3105,3402,4004,4005,5005,5049,6006,6031,6045,

%U 6048,6072,6075,6084,6105,6804,7007,7011,7128,7425,8008,8019,8092,8316,8712,9009

%N Numbers, not divisible by 10, whose digits can be permuted to get a proper divisor.

%H Robert Israel, <a href="/A096093/b096093.txt">Table of n, a(n) for n = 1..1000</a>

%e 105 is a term as 015 is a proper divisor of 105.

%e 2178 is a proper divisor of 8712 and 8712/2178=4.

%e 1089 is a proper divisor of 9801 and 9801/1089=9.

%p filter:= proc(n) local L,nL,P;

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

%p nL:= nops(L);

%p P:= subs(L=NULL, combinat:-permute(L));

%p ormap(p -> n mod add(p[i]*10^(i-1),i=1..nL) = 0, P)

%p end proc:

%p select(filter, [seq(seq(10*i+j,j=1..9),i=1..10000)]); # _Robert Israel_, Jun 01 2020

%t f[n_] := Union[ IntegerQ /@ Drop[ n/FromDigits /@ Permutations[IntegerDigits[n]], 1]][[ -1]]; Select[ Range[ 9015], Mod[ #, 10] != 0 && f[ # ] == True &] (* _Robert G. Wilson v_, Jun 23 2004 *)

%Y Cf. A096092.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Jun 22 2004

%E Edited, corrected and extended by _Robert G. Wilson v_, Jun 23 2004