A351478 Numbers whose sum of even digits is twice the sum of odd digits.
12, 21, 36, 63, 102, 114, 120, 138, 141, 183, 201, 210, 234, 243, 258, 285, 306, 318, 324, 342, 360, 381, 411, 423, 432, 456, 465, 528, 546, 564, 582, 603, 630, 645, 654, 678, 687, 768, 786, 813, 825, 831, 852, 867, 876, 1002, 1014, 1020, 1038, 1041, 1083, 1104, 1116, 1122, 1140, 1161, 1200, 1212
Offset: 1
Examples
a(1) = 12 whose sum of even digits (4) is twice the sum of odd digits (2); a(2) = 21 whose sum of even digits (4) is twice the sum of odd digits (2); a(3) = 36 whose sum of even digits (6) is twice the sum of odd digits (3); etc.
Programs
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Mathematica
Select[Range[1000], Plus @@ Select[IntegerDigits[#], EvenQ] == 2 * Plus @@ Select[IntegerDigits[#], OddQ] &] (* Amiram Eldar, Feb 12 2022 *)
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Python
def ok(n): ds = list(map(int, str(n))) return sum(d for d in ds if d%2==0) == 2*sum(d for d in ds if d%2==1) print([k for k in range(1, 2173) if ok(k)]) # Michael S. Branicky, Feb 12 2022
Comments