A039276 - OEIS

A039276

Numbers whose base-3 representation has the same nonzero number of 0's and 2's.

6, 11, 15, 19, 21, 32, 34, 38, 42, 46, 48, 56, 58, 60, 64, 66, 72, 89, 95, 97, 101, 103, 105, 113, 115, 119, 123, 127, 129, 137, 139, 141, 145, 147, 153, 167, 169, 173, 175, 177, 181, 183, 191, 193, 195, 199, 201, 207, 217, 219, 225, 260, 266, 268, 278, 284

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..56.

MATHEMATICA

Select[Range[300], DigitCount[#, 3, 0]==DigitCount[#, 3, 2]>0&] (* Harvey P. Dale, May 10 2011 *)

PROG

(Python)

from sympy.ntheory import count_digits

def ok(n): d = count_digits(n, 3); return 0 in d and 2 in d and d[0] == d[2]

print(list(filter(ok, range(285)))) # Michael S. Branicky, Jun 11 2021