A397629 Numbers m such that m mod floor(log_3(m)) = 0.

3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 84, 88, 92, 96, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 148, 152, 156, 160, 164, 168, 172, 176, 180, 184, 188, 192

Offset

1,1

Comments

Base 3 analog of A112249.

The asymptotic density of this sequence is 0 (Cooper and Kennedy, 1989).

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Curtis N. Cooper and Robert E. Kennedy, Chebyshev's inequality and natural density, Amer. Math. Monthly, Vol. 96, No. 2 (1989), pp. 118-124.

Mathematica

Select[Range[3, 200], Divisible[#, IntegerLength[#, 3] - 1] &] (* Paolo Xausa, Jul 03 2026 *)

Prog

(Python)
from sympy import integer_log
from oeis_sequences.OEISsequences import bisection
def A397629(n):
    def f(x):
        c, l, a = n+x, integer_log(x, 3)[0], 3
        for i in range(1, l):
            c += (a-1)//i
            a *= 3
            c -= (a-1)//i
        if l:
            c -= x//l-(a-1)//l
        return c
    return bisection(f, n, n)

Crossrefs

Cf. A062153, A112249.

Sequence in context: A039078 A073632 A066378 * A125684 A207669 A001272

Adjacent sequences: A397619 A397625 A397626 * A397630 A397631 A397632

Keyword

nonn,new

Author

Chai Wah Wu, Jul 02 2026

Status

approved