cp's OEIS Frontend

A032540 Numbers that, when expressed in base 4 and then interpreted in base 10, yield a multiple of the original number.

%I A032540 #26 Oct 25 2019 18:11:09
%S A032540 0,1,2,3,6,24,120,171,177,273,362,440,546,819,1418,1560,1582,1638,
%T A032540 1760,1806,2400,2841,2927,3640,4706,4882,5720,6328,6552,7040,7224,
%U A032540 9431,9600,10101,14560,20202,22880,24800,25080,25312,28896,32760,36974,38400
%N A032540 Numbers that, when expressed in base 4 and then interpreted in base 10, yield a multiple of the original number.
%C A032540 n such that A007090(n) is a multiple of n. - _Robert Israel_, Sep 13 2018
%H A032540 Giovanni Resta, <a href="/A032540/b032540.txt">Table of n, a(n) for n = 1..153</a> (terms < 5*10^12, first 100 terms from Robert Israel)
%e A032540 24 in base 4 is 120, which interpreted in base 10 is 120 = 5*24.
%p A032540 filter:= proc(n) local L,t;
%p A032540   L:= convert(n,base,4);
%p A032540   t:= add(L[i]*10^(i-1),i=1..nops(L));
%p A032540   t mod n = 0
%p A032540 end proc:
%p A032540 filter(0):=true:
%p A032540 select(filter, [$0..10^5]); # _Robert Israel_, Sep 13 2018
%t A032540 Join[{0}, Select[Range[40000], Divisible[FromDigits[IntegerDigits[#,4]], #]&]]  (* _Harvey P. Dale_, Apr 20 2011 *)
%Y A032540 Cf. A032539, A032541, A032532.
%K A032540 base,nonn
%O A032540 1,3
%A A032540 _Patrick De Geest_, Apr 15 1998
%E A032540 More terms from _Erich Friedman_ and _Naohiro Nomoto_, Aug 06 2001
%E A032540 Offset changed by _Robert Israel_, Sep 13 2018
%E A032540 Name edited by _Jon E. Schoenfield_, Oct 25 2019