

A332498


a(n) = y(w+1) where y(0) = 0 and y(k+1) = 2^(k+1)1y(k) (resp. y(k)) when d_k = 2 (resp. d_k <> 2) and Sum_{k=0..w} d_k*3^k is the ternary representation of n. Sequence A332497 gives corresponding x's.


2



0, 0, 1, 0, 0, 1, 3, 3, 2, 0, 0, 1, 0, 0, 1, 3, 3, 2, 7, 7, 6, 7, 7, 6, 4, 4, 5, 0, 0, 1, 0, 0, 1, 3, 3, 2, 0, 0, 1, 0, 0, 1, 3, 3, 2, 7, 7, 6, 7, 7, 6, 4, 4, 5, 15, 15, 14, 15, 15, 14, 12, 12, 13, 15, 15, 14, 15, 15, 14, 12, 12, 13, 8, 8, 9, 8, 8, 9, 11, 11
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OFFSET

0,7


LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..6560
Wikipedia, Tsquare (fractal)


FORMULA

a(n) = 0 iff n belongs to A005836.


EXAMPLE

For n = 42:
 the ternary representation of 42 is "1120",
 x(0) = 0,
 x(1) = x(0) = 0 (as d_0 = 0),
 x(2) = 2^21  x(1) = 3 (as d_1 = 2),
 x(3) = x(2) = 3 (as d_2 = 1 <> 2),
 x(4) = x(3) = 3 (as d_3 = 1 <> 2),
 hence a(42) = 3.


PROG

(PARI) a(n) = { my (y=0, k=1); while (n, if (n%3==2, y=2^k1y); n\=3; k++); y }


CROSSREFS

Cf. A005836, A332497 (corresponding x's and additional comments).
Sequence in context: A271082 A053375 A117252 * A181407 A114187 A016037
Adjacent sequences: A332495 A332496 A332497 * A332499 A332508 A332509


KEYWORD

nonn,base


AUTHOR

Rémy Sigrist, Feb 14 2020


STATUS

approved



