A257869 Nonnegative integers with an equal number of occurrences of all trits in balanced ternary representation.
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
Offset: 1
Examples
6 = 1L0_bal3, 8 = 10L_bal3, 136 = 1LL001_bal3, 138 = 1LL010_bal3, 144 = 1LL100_bal3, where L represents (-1).
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..10000
- Wikipedia, Balanced ternary
Programs
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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);
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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