cp's OEIS Frontend

A351478 Numbers whose sum of even digits is twice the sum of odd digits.

%I A351478 #14 Feb 12 2022 13:43:03
%S A351478 12,21,36,63,102,114,120,138,141,183,201,210,234,243,258,285,306,318,
%T A351478 324,342,360,381,411,423,432,456,465,528,546,564,582,603,630,645,654,
%U A351478 678,687,768,786,813,825,831,852,867,876,1002,1014,1020,1038,1041,1083,1104,1116,1122,1140,1161,1200,1212
%N A351478 Numbers whose sum of even digits is twice the sum of odd digits.
%C A351478 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 A351478 a(1) = 12 whose sum of even digits (4) is twice the sum of odd digits (2);
%e A351478 a(2) = 21 whose sum of even digits (4) is twice the sum of odd digits (2);
%e A351478 a(3) = 36 whose sum of even digits (6) is twice the sum of odd digits (3);
%e A351478 etc.
%t A351478 Select[Range[1000], Plus @@ Select[IntegerDigits[#], EvenQ] == 2 * Plus @@ Select[IntegerDigits[#], OddQ] &] (* _Amiram Eldar_, Feb 12 2022 *)
%o A351478 (Python)
%o A351478 def ok(n):
%o A351478     ds = list(map(int, str(n)))
%o A351478     return sum(d for d in ds if d%2==0) == 2*sum(d for d in ds if d%2==1)
%o A351478 print([k for k in range(1, 2173) if ok(k)]) # _Michael S. Branicky_, Feb 12 2022
%Y A351478 Cf. A036301, A351479.
%K A351478 base,nonn
%O A351478 1,1
%A A351478 _Eric Angelini_ and _Carole Dubois_, Feb 12 2022