A039001 Numbers whose base-3 representation has the same number of 1's and 2's.

0, 5, 7, 11, 15, 19, 21, 29, 33, 44, 45, 50, 52, 55, 57, 63, 68, 70, 76, 83, 87, 98, 99, 104, 106, 116, 128, 132, 135, 140, 142, 146, 150, 154, 156, 163, 165, 171, 176, 178, 184, 189, 194, 196, 200, 204, 208, 210, 220, 226, 228, 245, 249, 260, 261, 266, 268

Offset: 1

Author

Olivier Gérard

Keywords

• nonn
• base
• easy

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007089, A062756, A081603.

Programs

PARI

isok(m) = my(d=digits(m, 3)); #select(x->(x==1), d) == #select(x->(x==2), d); \\ Michel Marcus, Mar 23 2020