A290079 - OEIS

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A290079

Characteristic function for A249721: a(n) = 1 if there are either no 1-digits at all in base-3 representation of n, or if there are exactly two 1's next to each other, a(n) = 0 in any other cases.

1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0

(list; graph; refs; listen; history; text; internal format)

OFFSET

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..59049

Index entries for characteristic functions

FORMULA

If n is even and 9 ∤ C(n,n/2), then a(n) = 1, otherwise a(n) = 0.

EXAMPLE

n A007089(n) a(n) = 1 if 1-free, except for possibly a single 11-pair,

0 otherwise

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0 0 1