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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. 3
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

0

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

  ------------------

   0    0         1

   1    1         0

   2    2         1

   3   10         0

   4   11         1

   5   12         0

   6   20         1

   7   21         0

   8   22         1

   9  100         0

  10  101         0

  11  102         0

  12  110         1

  13  111         0

  14  112         1

  15  120         0

PROG

(PARI) A290079(n) = if((!(n%2)&&(binomial(n, n/2)%9)), 1, 0);

(Scheme) (define (A290079 n) (if (in_A249721? n) 1 0)) ;; See under A249721 for in_A249721?

CROSSREFS

Cf. A007089, A051382, A249721, A290093.

Sequence in context: A014269 A014229 A014149 * A011632 A015157 A015213

Adjacent sequences:  A290076 A290077 A290078 * A290080 A290081 A290082

KEYWORD

nonn,base

AUTHOR

Antti Karttunen, Jul 25 2017

STATUS

approved

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Last modified October 18 15:41 EDT 2019. Contains 328162 sequences. (Running on oeis4.)