A244042 In ternary representation of n, replace 2's with 0's.

0, 1, 0, 3, 4, 3, 0, 1, 0, 9, 10, 9, 12, 13, 12, 9, 10, 9, 0, 1, 0, 3, 4, 3, 0, 1, 0, 27, 28, 27, 30, 31, 30, 27, 28, 27, 36, 37, 36, 39, 40, 39, 36, 37, 36, 27, 28, 27, 30, 31, 30, 27, 28, 27, 0, 1, 0, 3, 4, 3, 0, 1, 0, 9, 10, 9, 12, 13, 12, 9, 10, 9

Offset

0,4

Links

Alois P. Heinz, Table of n, a(n) for n = 0..6560

Formula

a(n) = n - 2 * A005836(A289814(n) + 1) = A005836(A289813(n) + 1). - _Andrey Zabolotskiy_, Nov 11 2019

Example

16 = 121_3, replacing 2 with 0 gives 101_3 = 10, so a(16) = 10.

Maple

a:= proc(n) local t, r, i; t, r:= n, 0;
      for i from 0 while t>0 do
        r:= r+3^i*(d-> `if`(d=2, 0, d))(irem(t, 3, 't'))
      od; r
    end:
seq(a(n), n=0..80);  # _Alois P. Heinz_, Jun 17 2014

Mathematica

Array[FromDigits[IntegerDigits[#, 3] /. 2 -> 0, 3] &, 72, 0] (* _Michael De Vlieger_, Mar 17 2018 *)

Prog

(Python)
from sympy.ntheory.factor_ import digits
def a(n):return int("".join(map(str, digits(n, 3)[1:])).replace('2', '0'), 3) # _Indranil Ghosh_, Jun 10 2017
(PARI) a(n) = my(d=digits(n, 3)); fromdigits(apply(x->(if (x==2, 0, x)), d), 3); \\ _Michel Marcus_, Jun 10 2017

Crossrefs

Cf. A004488, A117966, A005836, A289813, A289814.

Sequence in context: A278214 A359601 A072681 * A318840 A318830 A242803

Adjacent sequences: A244039 A244040 A244041 * A244043 A244044 A244045

Keyword

nonn,base,look

Author

_Joonas Pohjonen_, Jun 17 2014

Status

approved