A163327 -id:A163327 - cp's OEIS frontend

A163333 Self-inverse permutation of integers: A163327-conjugate of A163332.

0, 7, 2, 3, 4, 5, 6, 1, 8, 69, 64, 71, 66, 67, 68, 63, 70, 65, 18, 25, 20, 21, 22, 23, 24, 19, 26, 29, 34, 27, 32, 31, 30, 35, 28, 33, 44, 37, 42, 41, 40, 39, 38, 43, 36, 47, 52, 45, 50, 49, 48, 53, 46, 51, 54, 61, 56, 57, 58, 59, 60, 55, 62, 15, 10, 17, 12, 13, 14, 9, 16, 11

Offset: 0

Antti Karttunen, Jul 29 2009

nonn

The integers [0,(9^k)-1] are confined to range [0,(9^k)-1].

a(n) = A163327(A163332(A163327(n))). A163334 & A163336 give two variants of the Peano curve in an N x N grid. Cf. also A163355.

A057300 Binary counter with odd/even bit positions swapped; base-4 counter with 1's replaced by 2's and vice versa.

Original entry on oeis.org

0, 2, 1, 3, 8, 10, 9, 11, 4, 6, 5, 7, 12, 14, 13, 15, 32, 34, 33, 35, 40, 42, 41, 43, 36, 38, 37, 39, 44, 46, 45, 47, 16, 18, 17, 19, 24, 26, 25, 27, 20, 22, 21, 23, 28, 30, 29, 31, 48, 50, 49, 51, 56, 58, 57, 59, 52, 54, 53, 55, 60, 62, 61, 63, 128, 130, 129, 131, 136, 138

Offset: 0

Marc LeBrun, Aug 24 2000

A self-inverse permutation of the integers.
a(n) = n if and only if n can be written as 3*Sum_{k>=0} d_i*4^k, where d_i is either 0 or 1. - Jon Perry, Oct 06 2012
From Veselin Jungic, Mar 03 2015: (Start)
In 1988 A. F. Sidorenko, see the Sidorenko reference, used this sequence as an example of a permutation of the set of positive integers with the property that if positive integers i, j, and k form a 3-term arithmetic progression then the corresponding terms a(i), a(j), and a(k) do not form an arithmetic progression.
In the terminology introduced in the Brown, Jungic, and Poelstra reference, the sequence does not contain "double 3-term arithmetic progressions".
It is not difficult to check that this sequence is with unbounded gaps, i.e., for any positive number m there is a natural number n such that a(n+1) - a(n) > m.
It is an open question if every sequence of integers with bounded gaps must contain a double 3-term arithmetic progression. This problem is equivalent to the well known additive square problem in infinite words: Is it true that any infinite word with a finite set of integers as its alphabet contains two consecutive blocks of the same length and the same sum? For more details about the additive square problem in infinite words see the following references: Ardal, et al.; Brown and Freedman; Freedman; Grytczuk; Halbeisen and Hungerbuhler, and Pirillo and Varricchio.
The sequence was attributed to Sidorenko in P. Hegarty's paper "Permutations avoiding arithmetic patterns". In his paper Hegarty characterized the countably infinite abelian groups for which there exists a bijection mapping arithmetic progressions to non-arithmetic progressions. This was further generalized by Jungic and Sahasrabudhe. (End)

			a(31) = a(4*7+3) = 4*a(7) + a(3) = 4*11 + 3 = 47.

Paul Tek, Table of n, a(n) for n = 0..16383
H. Ardal, T. Brown, V. Jungic, and J. Sahasrabudhe, On Additive and Abelian Complexity in Infinite Words, INTEGERS: Elect. J. Combin. Number Theory, 12 (2012), A21.
T. C. Brown and A. R. Freedman, Arithmetic progressions in lacunary sets, Rocky Mountain J. Math., 17 Number 3 (1987), 587-596. doi:10.1216/RMJ-1987-17-3-587
T. Brown, V. Jungic, and A. Poelstra, On 3-term double arithmetic progressions, INTEGERS: Elect. J. Combin. Number Theory, 14 (2014), A43.
A. R. Freedman, Sequences on sets of four numbers, INTEGERS: Elect. J. Combin. Number Theory, 16 (2016), A33.
J. Grytczuk, Thue type problems for graphs, points and numbers, Discrete Math., 308 (2008), 4419-4429.
L. Halbeisen and N. Hungerbuhler, An application of van der Waerden's theorem in additive number theory, INTEGERS: Elect. J. Combin. Number Theory, 0 (2000), A7.
Peter Hegarty, Permutations avoiding arithmetic patterns, The Electronic Journal of Combinatorics, 11 (2004), #R39.
V. Jungic and J. Sahasrabudhe, Permutations destroying arithmetic structure, The Electronic Journal of Combinatorics, Volume 22, Issue 2 (2015), Paper #P2.5.
G. Pirillo and S. Varricchio, On uniformly repetitive semigroups, Semigroup Forum, 49 (1994), 125-129.
A. F. Sidorenko, An infinite permutation without arithmetic progressions, Discrete Math., 69 (1988), 211.
Ralf Stephan, Some divide-and-conquer sequences ...
Ralf Stephan, Table of generating functions
Index entries for sequences related to binary expansion of n
Index entries for sequences that are permutations of the natural numbers

Sequences used in definitions of this sequence: A000695, A059905, A059906.
Sequences with similar definitions: A057301, A126006, A126007, A126008, A163241, A163327.
A003986, A003987, A004198, A053985, A054240 are used to express relationships between sequence terms.

#include 
uint32_t a(uint32_t n) { return ((n & 0x55555555) << 1) | ((n & 0xaaaaaaaa) >> 1); } /* Falk Hüffner, Jan 23 2022 */

a:= proc(n) option remember; `if`(n=0, 0,
      a(iquo(n, 4, 'r'))*4+[0, 2, 1, 3][r+1])
    end:
seq(a(n), n=0..69);  # Alois P. Heinz, Jan 25 2022

Table[FromDigits[IntegerDigits[n,4]/.{1->2,2->1},4],{n,0,70}] (* Harvey P. Dale, Aug 24 2017 *)

A057300(n) = { my(t=1,s=0); while(n>0, if(1==(n%4),n++,if(2==(n%4),n--)); s += (n%4)*t; n >>= 2; t <<= 2); (s); }; \\ Antti Karttunen, Apr 14 2018

Conjecture: a(2*n) = -2*a(n) + 5*n, a(2*n+1) = -2*a(n) + 5*n + 2. - Ralf Stephan, Oct 11 2003
a(4n+k) = 4a(n) + a(k), 0 <= k <= 3. - Jon Perry, Oct 06 2012
a(n) = A000695(A059906(n)) + 2*A000695(A059905(n)). - Antti Karttunen, Apr 14 2018
From Peter Munn, Dec 10 2019: (Start)
a(a(n)) = n.
a(A000695(m) + 2*A000695(n)) = 2*A000695(m) + A000695(n).
a(n OR k) = a(n) OR a(k), where OR is bitwise-or (A003986).
a(n XOR k) = a(n) XOR a(k), where XOR is bitwise exclusive-or (A003987).
a(n AND k) = a(n) AND a(k), where AND is bitwise-and (A004198).
a(A054240(n,k)) = A054240(a(n), a(k)). (End)
a(n) = 5*n/4 - 3*A053985(2*n)/8. - Alan Michael Gómez Calderón, May 20 2025

A163336 Peano curve in an n X n grid, starting downwards from the top left corner, listed antidiagonally as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Original entry on oeis.org

0, 5, 1, 6, 4, 2, 47, 7, 3, 15, 48, 46, 8, 14, 16, 53, 49, 45, 9, 13, 17, 54, 52, 50, 44, 10, 12, 18, 59, 55, 51, 39, 43, 11, 23, 19, 60, 58, 56, 38, 40, 42, 24, 22, 20, 425, 61, 57, 69, 37, 41, 29, 25, 21, 141, 426, 424, 62, 68, 70, 36, 30, 28, 26, 140, 142, 431, 427

Offset: 0

Antti Karttunen, Jul 29 2009

			The top left 9 X 9 corner of the array shows how this surjective self-avoiding walk begins (connect the terms in numerical order, 0-1-2-3-...):
   0  5  6 47 48 53 54 59 60
   1  4  7 46 49 52 55 58 61
   2  3  8 45 50 51 56 57 62
  15 14  9 44 39 38 69 68 63
  16 13 10 43 40 37 70 67 64
  17 12 11 42 41 36 71 66 65
  18 23 24 29 30 35 72 77 78
  19 22 25 28 31 34 73 76 79
  20 21 26 27 32 33 74 75 80

A. Karttunen, Table of n, a(n) for n = 0..3320
E. H. Moore, On Certain Crinkly Curves, Transactions of the American Mathematical Society, volume 1, number 1, 1900, pages 72-90. (And errata.) See section 7 (figure 3 with Y downwards is the table here).
Giuseppe Peano, Sur une courbe, qui remplit toute une aire plane, Mathematische Annalen, volume 36, number 1, 1890, pages 157-160. Also EUDML (link to GDZ).
Rémy Sigrist, Colored scatterplot of (x, y) such that 0 <= x, y < 3^6 (where the hue is function of T(x, y))
Eric Weisstein's World of Mathematics, Hilbert curve (this curve called "Hilbert II").
Wikipedia, Self-avoiding walk
Wikipedia, Space-filling curve
Index entries for sequences that are permutations of the natural numbers

Transpose: A163334. Inverse: A163337. a(n) = A163332(A163330(n)) = A163327(A163333(A163328(n))) = A163334(A061579(n)). One-based version: A163340. Row sums: A163342. Row 0: A163481. Column 0: A163480. Central diagonal: A163343.

See A163357 and A163359 for the Hilbert curve.

b[{n_, k_}, {m_}] := (A[n, k] = m - 1);
MapIndexed[b, List @@ PeanoCurve[4][[1]]];
Table[A[n - k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Mar 07 2021 *)

Name corrected by Kevin Ryde, Aug 28 2020

A163332 Self-inverse permutation of the integers for constructing the Peano curve in an N X N grid.

Original entry on oeis.org

0, 1, 2, 5, 4, 3, 6, 7, 8, 15, 16, 17, 14, 13, 12, 9, 10, 11, 18, 19, 20, 23, 22, 21, 24, 25, 26, 47, 46, 45, 48, 49, 50, 53, 52, 51, 44, 43, 42, 39, 40, 41, 38, 37, 36, 29, 28, 27, 30, 31, 32, 35, 34, 33, 54, 55, 56, 59, 58, 57, 60, 61, 62, 69, 70, 71, 68, 67, 66, 63, 64, 65

Offset: 0

Antti Karttunen, Jul 29 2009

nonn

The integers [0,(3^k)-1] are confined to range [0,(3^k)-1].
From Kevin Ryde, Sep 04 2020: (Start)
To calculate a(n), write n in ternary digits n[k],..,n[0], where n[0] is the least significant digit.  Then the ternary digits of a(n) are a[j] = k^{n[j+1]+n[j+3]+...}(n[j]) where Peano's complement operator k^{s}(d) = d if s even or 2-d if s odd.
A single complement is k(d) = 2-d and the "exponent" is repeats k(k(k(...))).  Sum s = n[j+1] + n[j+3] + ... is every second digit above j, so digit j flips 0 <-> 2 when an odd number of odd digits (1's) among these.  The complement does not change digit parity so a second transformation re-complements back to the original digits and so self-inverse a(a(n)) = n.
Peano's curve is formed by digits of a(n) put alternately to x and y coordinates, so a(n) maps between the Peano curve the ternary Z-order curve per the formulas in A163528, A163529.
(End)

Antti Karttunen, Table of n, a(n) for n = 0..59048
Giuseppe Peano, Sur une courbe, qui remplit toute une aire plane, Mathematische Annalen, volume 36, number 1, 1890, pages 157-160. Also EUDML (link to GDZ).
Index entries for sequences that are permutations of the natural numbers

Coordinates using this transform: A163528, A163529.
A163334 & A163336 give two variants of the Peano curve in an N X N grid.
Cf. A163355 (Hilbert curve).

a[n_] := FromDigits[With[{d = Reverse@IntegerDigits[n, 3]}, Reverse@Table[
  If[EvenQ@Total@d[[j+1 ;; ;; 2]], d[[j]], 2-d[[j]]], {j, Length@d}]], 3];
Array[a, 100] (* Andrey Zabolotskiy, Apr 08 2021, after Kevin Ryde *)

a(n) = my(v=digits(n,3)); for(start=2,3, my(s=0); forstep(i=start,#v,2, s+=v[i-1]; if(s%2,v[i]=2-v[i]))); fromdigits(v,3); \\ Kevin Ryde, Sep 04 2020

a(n) = A163327(A163333(A163327(n))).

Name corrected by Kevin Ryde, Aug 27 2020

A163325 Pick digits at the even distance from the least significant end of the ternary expansion of n, then convert back to decimal.

Original entry on oeis.org

0, 1, 2, 0, 1, 2, 0, 1, 2, 3, 4, 5, 3, 4, 5, 3, 4, 5, 6, 7, 8, 6, 7, 8, 6, 7, 8, 0, 1, 2, 0, 1, 2, 0, 1, 2, 3, 4, 5, 3, 4, 5, 3, 4, 5, 6, 7, 8, 6, 7, 8, 6, 7, 8, 0, 1, 2, 0, 1, 2, 0, 1, 2, 3, 4, 5, 3, 4, 5, 3, 4, 5, 6, 7, 8, 6, 7, 8, 6, 7, 8, 9, 10, 11, 9, 10, 11, 9, 10, 11, 12, 13, 14, 12, 13, 14

Offset: 0

Antti Karttunen, Jul 29 2009

			11 in ternary base (A007089) is written as '102' (1*9 + 0*3 + 2), from which we pick the "zeroth" and 2nd digits from the right, giving '12' = 1*3 + 2 = 5, thus a(11) = 5.

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

A059905 is an analogous sequence for binary.

Cf. A007089, A163327, A163328, A163329.

a(n) = fromdigits(digits(n,9)%3,3); \\ Kevin Ryde, May 14 2020

a(0) = 0, a(n) = (n mod 3) + 3*a(floor(n/9)).
a(n) = Sum_{k>=0} {A030341(n,k)*b(k)} where b is the sequence (1,0,3,0,9,0,27,0,81,0,243,0... = A254006): powers of 3 alternating with zeros. - Philippe Deléham, Oct 22 2011
A037314(a(n)) + 3*A037314(A163326(n)) = n for all n.

Edited by Charles R Greathouse IV, Nov 01 2009

A163328 Square array A, where entry A(y,x) has the ternary digits of x interleaved with the ternary digits of y, converted back to decimal. Listed by antidiagonals: A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Original entry on oeis.org

0, 1, 3, 2, 4, 6, 9, 5, 7, 27, 10, 12, 8, 28, 30, 11, 13, 15, 29, 31, 33, 18, 14, 16, 36, 32, 34, 54, 19, 21, 17, 37, 39, 35, 55, 57, 20, 22, 24, 38, 40, 42, 56, 58, 60, 81, 23, 25, 45, 41, 43, 63, 59, 61, 243, 82, 84, 26, 46, 48, 44, 64, 66, 62, 244, 246, 83, 85, 87, 47, 49

Offset: 0

Antti Karttunen, Jul 29 2009

			From _Kevin Ryde_, Oct 06 2020: (Start)
Array A(y,x) read by downwards antidiagonals, so 0, 1,3, 2,4,6, etc.
        x=0   1   2   3   4   5   6   7   8
      +--------------------------------------
  y=0 |   0,  1,  2,  9, 10, 11, 18, 19, 20,
    1 |   3,  4,  5, 12, 13, 14, 21, 22,
    2 |   6,  7,  8, 15, 16, 17, 24,
    3 |  27, 28, 29, 36, 37, 38,
    4 |  30, 31, 32, 39, 40,
    5 |  33, 34, 35, 42,
    6 |  54, 55, 56,
    7 |  57, 58,
    8 |  60,
(End)

Antti Karttunen, Table of n, a(n) for n = 0..3320
Index entries for sequences that are permutations of the natural numbers

Inverse: A163329. Transpose: A163330. Cf. A037314 (row y=0), A208665 (column x=0)

Cf. A054238 is an analogous sequence for binary. Cf. A007089, A163327, A163332, A163334.

A(y,x) = 3*fromdigits(digits(y,3),9) + fromdigits(digits(x,3),9); \\ Kevin Ryde, Oct 06 2020

(define (A163328 n) (+ (A037314 (A025581 n)) (* 3 (A037314 (A002262 n)))))

a(n) = A037314(A025581(n)) + 3*A037314(A002262(n))

a(n) = A163327(A163330(n)).

Edited by Charles R Greathouse IV, Nov 01 2009

A163326 Pick digits at the odd distance from the least significant end of the ternary expansion of n, then convert back to decimal.

Original entry on oeis.org

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

Offset: 0

Antti Karttunen, Jul 29 2009

			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.

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

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

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

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

Edited by Charles R Greathouse IV, Nov 01 2009

A163329 Inverse permutation to A163328.

Original entry on oeis.org

0, 1, 3, 2, 4, 7, 5, 8, 12, 6, 10, 15, 11, 16, 22, 17, 23, 30, 21, 28, 36, 29, 37, 46, 38, 47, 57, 9, 13, 18, 14, 19, 25, 20, 26, 33, 24, 31, 39, 32, 40, 49, 41, 50, 60, 48, 58, 69, 59, 70, 82, 71, 83, 96, 27, 34, 42, 35, 43, 52, 44, 53, 63, 51, 61, 72, 62, 73, 85, 74, 86, 99

Offset: 0

Antti Karttunen, Jul 29 2009

nonn

Inverse: A163328. a(n) = A163331(A163327(n)). A054239 is an analogous sequence for binary. Cf. A007089.

(define (A163329 n) (A001477bi (A163325 n) (A163326 n)))
(define (A001477bi x y) (/ (+ (expt (+ x y) 2) x (* 3 y)) 2))

a(n) = A001477bi(A163325(n),A163326(n)), where A001477bi(x,y) = (((x+y)^2)+x+(3y))/2.

A163330 Square array A, where entry A(y,x) has the ternary digits of y interleaved with the ternary digits of x, converted back to decimal. Listed by antidiagonals: A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Original entry on oeis.org

0, 3, 1, 6, 4, 2, 27, 7, 5, 9, 30, 28, 8, 12, 10, 33, 31, 29, 15, 13, 11, 54, 34, 32, 36, 16, 14, 18, 57, 55, 35, 39, 37, 17, 21, 19, 60, 58, 56, 42, 40, 38, 24, 22, 20, 243, 61, 59, 63, 43, 41, 45, 25, 23, 81, 246, 244, 62, 66, 64, 44, 48, 46, 26, 84, 82, 249, 247, 245

Offset: 0

Antti Karttunen, Jul 29 2009

Inverse: A163331. a(n) = A163327(A163328(n)). Transpose: A163328. Cf. A007089, A163327, A163332, A163334.

(define (A163330 n) (+ (A037314 (A002262 n)) (* 3 (A037314 (A025581 n)))))

a(n) = 3*A037314(A025581(n)) + A037314(A002262(n))

A163331 Inverse permutation to A163330.

Original entry on oeis.org

0, 2, 5, 1, 4, 8, 3, 7, 12, 9, 14, 20, 13, 19, 26, 18, 25, 33, 27, 35, 44, 34, 43, 53, 42, 52, 63, 6, 11, 17, 10, 16, 23, 15, 22, 30, 24, 32, 41, 31, 40, 50, 39, 49, 60, 51, 62, 74, 61, 73, 86, 72, 85, 99, 21, 29, 38, 28, 37, 47, 36, 46, 57, 48, 59, 71, 58, 70, 83, 69, 82, 96

Offset: 0

Antti Karttunen, Jul 29 2009

Antti Karttunen, Table of n, a(n) for n = 0..6560
Index entries for sequences that are permutations of the natural numbers

Inverse: A163330. a(n) = A163329(A163327(n)). Cf. A007089.

(define (A163331 n) (A001477bi (A163326 n) (A163325 n)))
(define (A001477bi x y) (/ (+ (expt (+ x y) 2) x (* 3 y)) 2))

a(n) = A001477bi(A163326(n),A163325(n)), where A001477bi(x,y) = (((x+y)^2)+x+(3y))/2.

cp's OEIS Frontend

A163333 Self-inverse permutation of integers: A163327-conjugate of A163332.

Views

Author

Keywords

Comments

Links

Crossrefs

A057300 Binary counter with odd/even bit positions swapped; base-4 counter with 1's replaced by 2's and vice versa.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

C

Maple

Mathematica

PARI

Formula

A163336 Peano curve in an n X n grid, starting downwards from the top left corner, listed antidiagonally as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

Mathematica

Extensions

A163332 Self-inverse permutation of the integers for constructing the Peano curve in an N X N grid.

Views

Author

Keywords

Comments

Links

Crossrefs

Programs

Mathematica

PARI

Formula

Extensions

A163325 Pick digits at the even distance from the least significant end of the ternary expansion of n, then convert back to decimal.

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

PARI

Formula

Extensions

A163328 Square array A, where entry A(y,x) has the ternary digits of x interleaved with the ternary digits of y, converted back to decimal. Listed by antidiagonals: A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

PARI

Scheme

Formula

Extensions

A163326 Pick digits at the odd distance from the least significant end of the ternary expansion of n, then convert back to decimal.

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

PARI

Formula

Extensions

A163329 Inverse permutation to A163328.

Views