A163326 - OEIS

A163326

Pick digits at the odd distance from the least significant end of the ternary expansion of n, then convert back to decimal.

0, 0, 0, 1, 1, 1, 2, 2, 2, 0, 0, 0, 1, 1, 1, 2, 2, 2, 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 3, 3, 3, 4, 4, 4, 5, 5, 5, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 6, 6, 6, 7, 7, 7, 8, 8, 8, 6, 6, 6, 7, 7, 7, 8, 8, 8, 0, 0, 0, 1, 1, 1, 2, 2, 2, 0, 0, 0, 1, 1, 1, 2, 2, 2, 0, 0, 0

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

OFFSET

0,7

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..728

Kevin Ryde, Plot2 of X=A163325,Y=A163326, illustrating the ternary Z-order curve.

Index entries for sequences related to coordinates of 2D curves

FORMULA

a(n) = A163325(floor(n/3))

a(n) = Sum_{k>=0} A030341(n,k)*b(k) with (b) = (0,1,0,3,0,9,0,27,0,81,0,243,0,...): powers of 3 alternating with zeros. - Philippe Deléham, Oct 22 2011

EXAMPLE

42 in ternary base (A007089) is written as '1120' (1*27 + 1*9 + 2*3 + 0), from which we pick the first and 3rd digits from the right (zero-based!), giving '12' = 1*3 + 2 = 5, thus a(42) = 5.

PROG

(PARI) a(n) = fromdigits(digits(n, 9)\3, 3); \\ Kevin Ryde, May 15 2020

CROSSREFS

A059906 is an analogous sequence for binary. Note that A037314(A163325(n)) + 3*A037314(A163326(n)) = n for all n. Cf. A007089, A163327-A163329.

Sequence in context: A180834 A214458 A133873 * A028953 A348648 A037865

Adjacent sequences: A163323 A163324 A163325 * A163327 A163328 A163329

KEYWORD

nonn,base

AUTHOR

Antti Karttunen, Jul 29 2009

EXTENSIONS

Edited by Charles R Greathouse IV, Nov 01 2009

STATUS

approved