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A257869 Nonnegative integers with an equal number of occurrences of all trits in balanced ternary representation. 5
6, 8, 136, 138, 144, 154, 156, 160, 164, 168, 170, 180, 186, 188, 208, 210, 214, 218, 222, 224, 232, 236, 248, 258, 260, 266, 288, 294, 296, 312, 314, 320, 3406, 3412, 3414, 3430, 3432, 3438, 3484, 3486, 3492, 3510, 3568, 3574, 3576, 3592, 3594, 3600, 3622 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Wikipedia, Balanced ternary

EXAMPLE

6 = 1L0_bal3, 8 = 10L_bal3, 136 = 1LL001_bal3, 138 = 1LL010_bal3, 144 = 1LL100_bal3, where L represents (-1).

MAPLE

p:= proc(n) local d, m, r; m:=n; r:=0;

      while m>0 do

        d:= irem(m, 3, 'm');

        if d=2 then m:=m+1 fi;

        r:= r+x^d

      od;

      simplify(r/(1+x+x^2))::integer

    end:

a:= proc(n) option remember; local k;

      for k from 1+`if`(n=1, 0, a(n-1)) by 1

      while not p(k) do od; k

    end:

seq(a(n), n=1..70);

PROG

(Python)

def a(n):

    s=[]

    x=0

    while n>0:

        x=n%3

        n//=3

        if x==2:

            x=-1

            n+=1

        s.append(x)

    return s

print([n for n in range(1, 5001) if a(n).count(1)==a(n).count(-1) and a(n).count(-1)==a(n).count(0)]) # Indranil Ghosh, Jun 07 2017

CROSSREFS

Cf. A117967, A140267, A257867, A257868, A258410.

Subsequence of A174658.

Sequence in context: A324987 A013239 A013235 * A201387 A013236 A013242

Adjacent sequences:  A257866 A257867 A257868 * A257870 A257871 A257872

KEYWORD

nonn,base

AUTHOR

Alois P. Heinz, May 11 2015

STATUS

approved

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Last modified June 21 19:12 EDT 2021. Contains 345365 sequences. (Running on oeis4.)