cp's OEIS Frontend

A351479 Numbers whose sum of odd digits is twice the sum of even digits.

%I A351479 #13 Feb 12 2022 13:43:16
%S A351479 123,132,147,174,213,231,312,321,345,354,369,396,417,435,453,471,534,
%T A351479 543,567,576,639,657,675,693,714,741,756,765,789,798,879,897,936,963,
%U A351479 978,987,1023,1032,1047,1074,1203,1227,1230,1272,1302,1320,1407,1470,1704,1722,1740,2013,2031,2103,2127,2130,2172
%N A351479 Numbers whose sum of odd digits is twice the sum of even digits.
%C A351479 The sequence is closed under concatenation (if k and m are terms, so are k.m and m.k); permutation of a term's string of digits; and insertion of 0's within a term's string of digits. - _Michael S. Branicky_, Feb 12 2022
%e A351479 a(1) = 123 whose sum of odd digits (4) is twice the sum of even digits (2);
%e A351479 a(2) = 132 whose sum of odd digits (4) is twice the sum of even digits (2);
%e A351479 a(3) = 147 whose sum of odd digits (8) is twice the sum of even digits (4).
%t A351479 Select[Range[2000], Plus @@ Select[IntegerDigits[#], OddQ] == 2 * Plus @@ Select[IntegerDigits[#], EvenQ] &] (* _Amiram Eldar_, Feb 12 2022 *)
%o A351479 (Python)
%o A351479 def ok(n):
%o A351479     ds = list(map(int, str(n)))
%o A351479     return sum(d for d in ds if d%2==1) == 2*sum(d for d in ds if d%2==0)
%o A351479 print([k for k in range(1, 2173) if ok(k)]) # _Michael S. Branicky_, Feb 12 2022
%Y A351479 Cf. A036301, A351478.
%K A351479 base,nonn
%O A351479 1,1
%A A351479 _Carole Dubois_ and _Eric Angelini_, Feb 12 2022