A140268 - OEIS

A140268

a(n) = negative integer -n presented in balanced ternary system.

2, 21, 20, 22, 211, 210, 212, 201, 200, 202, 221, 220, 222, 2111, 2110, 2112, 2101, 2100, 2102, 2121, 2120, 2122, 2011, 2010, 2012, 2001, 2000, 2002, 2021, 2020, 2022, 2211, 2210, 2212, 2201, 2200, 2202, 2221, 2220, 2222, 21111, 21110, 21112

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OFFSET

1,1

COMMENTS

Sequence A117968 in ternary. (See there for more references.)

LINKS

Table of n, a(n) for n=1..43.

EXAMPLE

For example a(2) = 21, as -2 = -1*3 + 1*1.

Similarly, a(19) = 2102, as -19 = -1*27 + 1*9 + 0*3 + -1*1.

PROG

(Python)

from sympy.ntheory.factor_ import digits

def a117968(n):

if n==1: return 2

if n%3==0: return 3*a117968(n/3)

elif n%3==1: return 3*a117968((n - 1)/3) + 2

else: return 3*a117968((n + 1)/3) + 1

def a(n): return int("".join(map(str, digits(a117968(n), 3)[1:]))) # Indranil Ghosh, Jun 06 2017

CROSSREFS

a(n) = A007089(A117968(n)). Cf. A140267.

Sequence in context: A321534 A212483 A084313 * A106422 A320523 A371060

Adjacent sequences: A140265 A140266 A140267 * A140269 A140270 A140271

KEYWORD

nonn,base

AUTHOR

Antti Karttunen, May 19 2008, prompted by Eric Angelini's posting on SeqFan mailing list on Sep 15 2005.

STATUS

approved