A348706 - OEIS

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A348706

Delete all 0's from ternary expansion of n.

1, 2, 1, 4, 5, 2, 7, 8, 1, 4, 5, 4, 13, 14, 5, 16, 17, 2, 7, 8, 7, 22, 23, 8, 25, 26, 1, 4, 5, 4, 13, 14, 5, 16, 17, 4, 13, 14, 13, 40, 41, 14, 43, 44, 5, 16, 17, 16, 49, 50, 17, 52, 53, 2, 7, 8, 7, 22, 23, 8, 25, 26, 7, 22, 23, 22, 67, 68, 23, 70, 71, 8, 25

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

OFFSET

1,2

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..6561

FORMULA

a(n) <= n with equality iff n belongs to A032924.

EXAMPLE

The first terms, in decimal and in base 3, are:

n a(n) ter(n) ter(a(n))

-- ---- ------ ---------

1 1 1 1

2 2 2 2

3 1 10 1

4 4 11 11

5 5 12 12

6 2 20 2

7 7 21 21

8 8 22 22

9 1 100 1

10 4 101 11

11 5 102 12

12 4 110 11

13 13 111 111

14 14 112 112

15 5 120 12

MATHEMATICA

a[n_] := FromDigits[DeleteCases[IntegerDigits[n, 3], 0], 3]; Array[a, 100] (* Amiram Eldar, Oct 31 2021 *)

PROG

(PARI) a(n, base=3) = fromdigits(select(sign, digits(n, base)), base)

(Python)

from gmpy2 import digits

def A348706(n): return int(digits(n, 3).replace('0', ''), 3) # Chai Wah Wu, Nov 02 2021

CROSSREFS

Cf. A004719 (decimal analog), A032924 (fixed points), A038573 (binary analog).

Sequence in context: A308364 A210707 A078606 * A343250 A065518 A072012

Adjacent sequences: A348703 A348704 A348705 * A348707 A348708 A348709

KEYWORD

nonn,base,easy

AUTHOR

Rémy Sigrist, Oct 30 2021

STATUS

approved