A325913 - OEIS

A325913

Integers m such that there are exactly two powers of 2 between 3^m and 3^(m+1).

1, 3, 5, 6, 8, 10, 11, 13, 15, 17, 18, 20, 22, 23, 25, 27, 29, 30, 32, 34, 35, 37, 39, 41, 42, 44, 46, 47, 49, 51, 52, 54, 56, 58, 59, 61, 63, 64, 66, 68, 70, 71, 73, 75, 76, 78, 80, 82, 83, 85, 87, 88, 90, 92, 94, 95, 97, 99, 100

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Or m such that A022921(m) = 2.

Also largest m such that 2^(m+n) > 3^m. - Bob Selcoe, Dec 19 2021

LINKS

Benjamin Lombardo, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = floor(n/(log_2(3)-1)).

a(n) = A054414(n) - n - 1.

EXAMPLE

For m=3, there are exactly two powers of 2 between 3^3 = 27 and 3^(3+1) = 81: 32 and 64, since 27 < 32 < 64 < 81. Therefore, m=3 is an element of the sequence (at n=2).

PROG

(Python)

import math

def a(n):

return math.floor(n/(math.log2(3)-1))

for n in range(1, 101):

print("a(" + str(n) + ") = " + str(a(n)))

CROSSREFS

Cf. A022921, A054414.

Sequence in context: A059541 A189682 A003152 * A283965 A193599 A068125

Adjacent sequences: A325910 A325911 A325912 * A325914 A325915 A325916

KEYWORD

nonn

AUTHOR

Benjamin Lombardo, Sep 08 2019

STATUS

approved