A036301 -id:A036301 - cp's OEIS frontend

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

Eric Angelini and Carole Dubois, Feb 12 2022

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

			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.

Cf. A036301, A351479.

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

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

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

Original entry on oeis.org

123, 132, 147, 174, 213, 231, 312, 321, 345, 354, 369, 396, 417, 435, 453, 471, 534, 543, 567, 576, 639, 657, 675, 693, 714, 741, 756, 765, 789, 798, 879, 897, 936, 963, 978, 987, 1023, 1032, 1047, 1074, 1203, 1227, 1230, 1272, 1302, 1320, 1407, 1470, 1704, 1722, 1740, 2013, 2031, 2103, 2127, 2130, 2172

Offset: 1

Carole Dubois and Eric Angelini, Feb 12 2022

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

			a(1) = 123 whose sum of odd digits (4) is twice the sum of even digits (2);
a(2) = 132 whose sum of odd digits (4) is twice the sum of even digits (2);
a(3) = 147 whose sum of odd digits (8) is twice the sum of even digits (4).

Cf. A036301, A351478.

Select[Range[2000], Plus @@ Select[IntegerDigits[#], OddQ] == 2 * Plus @@ Select[IntegerDigits[#], EvenQ] &] (* Amiram Eldar, Feb 12 2022 *)

def ok(n):
    ds = list(map(int, str(n)))
    return sum(d for d in ds if d%2==1) == 2*sum(d for d in ds if d%2==0)
print([k for k in range(1, 2173) if ok(k)]) # Michael S. Branicky, Feb 12 2022

A103877 Position of n in rearrangement of natural numbers A103849.

Original entry on oeis.org

1, 3, 4, 6, 7, 9, 10, 12, 13, 15, 18, 21, 16, 24, 19, 27, 22, 30, 25, 33, 28, 31, 34, 36, 37, 39, 40, 42, 43, 45, 48, 51, 54, 57, 46, 60, 49, 63, 52, 66, 55, 58, 61, 64

Offset: 0

Zak Seidov, Feb 20 2005

a(43)=64 because 43 in 64th place in A103849.

Cf. A036301, A103829, A103848, A103849.

Flatten[Table[Position[A103849, i], {i, 0, 43}]]

cp's OEIS Frontend

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

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

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Python

A103877 Position of n in rearrangement of natural numbers A103849.

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Mathematica