The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A163327 Self-inverse permutation of integers: swap the odd- and even-positioned digits in the ternary expansion of n, then convert back to decimal. 11
 0, 3, 6, 1, 4, 7, 2, 5, 8, 27, 30, 33, 28, 31, 34, 29, 32, 35, 54, 57, 60, 55, 58, 61, 56, 59, 62, 9, 12, 15, 10, 13, 16, 11, 14, 17, 36, 39, 42, 37, 40, 43, 38, 41, 44, 63, 66, 69, 64, 67, 70, 65, 68, 71, 18, 21, 24, 19, 22, 25, 20, 23, 26, 45, 48, 51, 46, 49, 52, 47, 50, 53 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Antti Karttunen, Table of n, a(n) for n = 0..728 Index entries for sequences that are permutations of the natural numbers FORMULA a(n) = A037314(A163326(n)) + 3*A037314(A163325(n)) EXAMPLE 11 in ternary base (A007089) is written as '(000...)102' (... + 0*27 + 1*9 + 0*3 + 2), which results '1020' = 1*27 + 0*9 + 2*3 + 0 = 33, when the odd- and even-positioned digits are swapped, thus a(11) = 33. PROG (Scheme) (define (A163327 n) (+ (A037314 (A163326 n)) (* 3 (A037314 (A163325 n))))) (Python) from sympy.ntheory import digits def a(n): d = digits(n, 3)[1:] return sum(3**(i+(1-2*(i&1)))*di for i, di in enumerate(d[::-1])) print([a(n) for n in range(72)]) # Michael S. Branicky, Aug 05 2022 CROSSREFS Cf. A007089, A163328-A163329. Other bases: A057300, A126006, A217558. Sequence in context: A199795 A200358 A181099 * A338460 A175032 A078768 Adjacent sequences: A163324 A163325 A163326 * A163328 A163329 A163330 KEYWORD nonn,base,look AUTHOR Antti Karttunen, Jul 29 2009 EXTENSIONS Edited by Charles R Greathouse IV, Nov 01 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 12 13:41 EDT 2024. Contains 375113 sequences. (Running on oeis4.)