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

1,1

Comments

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

Links

Table of n, a(n) for n=1..58.

Example

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.

Mathematica

Select[Range[1000], Plus @@ Select[IntegerDigits[#], EvenQ] == 2 * Plus @@ Select[IntegerDigits[#], OddQ] &] (* Amiram Eldar, Feb 12 2022 *)

Prog

(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

Crossrefs

Cf. A036301, A351479.

Sequence in context: A241503 A226186 A325301 * A219542 A354984 A367357

Adjacent sequences: A351475 A351476 A351477 * A351479 A351480 A351481

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Feb 12 2022

Status

approved