A350775 - OEIS

A350775

The balanced ternary expansion of a(n) is obtained by multiplying adjacent digits in the balanced ternary expansion of n: a(Sum_{k >= 0} t_k * 3^k) = Sum_{k >= 0} t_k * t_{k+1} * 3^k (with -1 <= t_k <= 1 for any k >= 0).

0, 0, -1, 0, 1, -2, -3, -4, 0, 0, 0, 2, 3, 4, -5, -6, -7, -9, -9, -9, -13, -12, -11, 1, 0, -1, 0, 0, 0, -1, 0, 1, 7, 6, 5, 9, 9, 9, 11, 12, 13, -14, -15, -16, -18, -18, -18, -22, -21, -20, -26, -27, -28, -27, -27, -27, -28, -27, -26, -38, -39, -40, -36, -36

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OFFSET

0,6

COMMENTS

This sequence is to balanced ternary what A048735 is to binary, or what A330633 is to decimal.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..9841

FORMULA

a(n) = 0 iff n belongs to A350776.

EXAMPLE

The first terms, in decimal and in balanced ternary, are:

n a(n) bter(n) bter(a(n))

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

0 0 0 0

1 0 1 0

2 -1 1T T

3 0 10 0

4 1 11 1

5 -2 1TT T1

6 -3 1T0 T0

7 -4 1T1 TT

8 0 10T 0

9 0 100 0

10 0 101 0

11 2 11T 1T

12 3 110 10

13 4 111 11

PROG

(PARI) a(n) = { my (v=0, p=0, d); for (x=-1, oo, if (n==0, return (v), d=[0, 1, -1][1+n%3]; v+=p*d*3^x; n=(n-d)/3; p=d)) }

CROSSREFS

Cf. A048735, A059095, A330633, A350776.

Sequence in context: A347716 A037847 A037883 * A330267 A023868 A122275

Adjacent sequences: A350772 A350773 A350774 * A350776 A350777 A350778

KEYWORD

sign,base

AUTHOR

Rémy Sigrist, Jan 15 2022

STATUS

approved