cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-7 of 7 results.

A163334 Peano curve in an n X n grid, starting rightwards 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, 1, 5, 2, 4, 6, 15, 3, 7, 47, 16, 14, 8, 46, 48, 17, 13, 9, 45, 49, 53, 18, 12, 10, 44, 50, 52, 54, 19, 23, 11, 43, 39, 51, 55, 59, 20, 22, 24, 42, 40, 38, 56, 58, 60, 141, 21, 25, 29, 41, 37, 69, 57, 61, 425, 142, 140, 26, 28, 30, 36, 70, 68, 62, 424, 426, 143, 139
Offset: 0

Views

Author

Antti Karttunen, Jul 29 2009

Keywords

Examples

			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  1  2 15 16 17 18 19 20
   5  4  3 14 13 12 23 22 21
   6  7  8  9 10 11 24 25 26
  47 46 45 44 43 42 29 28 27
  48 49 50 39 40 41 30 31 32
  53 52 51 38 37 36 35 34 33
  54 55 56 69 70 71 72 73 74
  59 58 57 68 67 66 77 76 75
  60 61 62 63 64 65 78 79 80
		

Crossrefs

Transpose: A163336. Inverse: A163335. One-based version: A163338. Row sums: A163342. Row 0: A163480. Column 0: A163481. Central diagonal: A163343.
See A163357 and A163359 for the Hilbert curve.

Programs

  • Mathematica
    b[{n_, k_}, {m_}] := (A[k, n] = 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 *)

Formula

a(n) = A163332(A163328(n)).

Extensions

Links to further derived sequences added by Antti Karttunen, Sep 21 2009
Name corrected by Kevin Ryde, Aug 22 2020

A163528 The X-coordinate of the n-th point in the Peano curve A163334.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Aug 01 2009

Keywords

Comments

There is a 2-state automaton that accepts exactly those pairs (n,a(n)) where n is represented in base 9 and a(n) in base 3; see accompanying file a163528.pdf - Jeffrey Shallit, Aug 10 2023

Crossrefs

Formula

a(n) = A025581(A163335(n)) = A002262(A163337(n)) = A163325(A163332(n)).

Extensions

Name corrected by Kevin Ryde, Aug 28 2020

A163529 The Y-coordinate of the n-th point in the Peano curve A163334.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Aug 01 2009

Keywords

Comments

There is a 2-state automaton that accepts exactly those pairs (n,a(n)) where n is represented in base 9 and a(n) in base 3; see accompanying file a163529.pdf. - Jeffrey Shallit, Aug 10 2023

Crossrefs

Formula

a(n) = A002262(A163335(n)) = A025581(A163337(n)) = A163326(A163332(n)).

Extensions

Name corrected by Kevin Ryde, Aug 28 2020

A163337 Inverse permutation to A163336.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 29 2009

Keywords

Comments

abs(A025581(a(n+1))-A025581(a(n))) + abs(A002262(a(n+1))-A002262(a(n))) = 1 for all n.

Crossrefs

Inverse: A163336. a(n) = A163331(A163332(n)) = A061579(A163335(n)). One-based version: A163341. See also A163335, A163358.

A166041 Permutation of nonnegative integers: a(n) tells which integer is in the same position in the square array A163357 as where n is located in the array A163334.

Original entry on oeis.org

0, 1, 14, 13, 2, 3, 4, 7, 8, 11, 30, 29, 18, 17, 12, 15, 16, 19, 20, 21, 234, 233, 22, 23, 24, 25, 230, 229, 26, 27, 36, 37, 218, 217, 38, 39, 34, 33, 52, 53, 32, 35, 28, 31, 10, 9, 6, 5, 58, 57, 54, 55, 56, 59, 60, 61, 50, 49, 62, 63, 64, 67, 68, 69, 122, 123, 44, 47, 48
Offset: 0

Views

Author

Antti Karttunen, Oct 06 2009

Keywords

Comments

Fixed points are quite rare: A165465.

Examples

			The top left 9 X 9 corner of A163334:
   0  1  2 15 16 17 18 19 20
   5  4  3 14 13 12 23 22 21
   6  7  8  9 10 11 24 25 26
  47 46 45 44 43 42 29 28 27
  48 49 50 39 40 41 30 31 32
  53 52 51 38 37 36 35 34 33
  54 55 56 69 70 71 72 73 74
  59 58 57 68 67 66 77 76 75
  60 61 62 63 64 65 78 79 80
The top left 8 X 8 corner of A163357:
   0  1 14 15 16 19 20 21
   3  2 13 12 17 18 23 22
   4  7  8 11 30 29 24 25
   5  6  9 10 31 28 27 26
  58 57 54 53 32 35 36 37
  59 56 55 52 33 34 39 38
  60 61 50 51 46 45 40 41
  63 62 49 48 47 44 43 42
9 is in position (2,3) in A163334, while A163357(2,3) = 11. Thus a(9) = 11.
		

Crossrefs

Inverse: A166042. a(n) = A163357(A163335(n)) = A163359(A163337(n)). Cf. also A166043.

A166043 Permutation of nonnegative integers: a(n) tells which integer is in the same position in the square array A163357 as where n is located in the array A163336.

Original entry on oeis.org

0, 3, 4, 7, 2, 1, 14, 13, 8, 9, 54, 55, 56, 57, 6, 5, 58, 59, 60, 63, 64, 67, 62, 61, 50, 49, 68, 69, 48, 51, 46, 47, 122, 123, 44, 45, 34, 35, 28, 31, 32, 33, 52, 53, 10, 11, 12, 15, 16, 17, 30, 29, 18, 19, 20, 23, 24, 25, 22, 21, 234, 233, 230, 229, 218, 217, 38, 37, 26
Offset: 0

Views

Author

Antti Karttunen, Oct 06 2009

Keywords

Comments

Fixed points are quite rare: A165467.

Examples

			The top left 9 X 9 corner of A163336:
   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
The top left 8 X 8 corner of A163357:
   0  1 14 15 16 19 20 21
   3  2 13 12 17 18 23 22
   4  7  8 11 30 29 24 25
   5  6  9 10 31 28 27 26
  58 57 54 53 32 35 36 37
  59 56 55 52 33 34 39 38
  60 61 50 51 46 45 40 41
  63 62 49 48 47 44 43 42
3 is in position (2,1) in A163336, while A163357(2,1) = 7. Thus a(3) = 7.
		

Crossrefs

Inverse: A166044. a(n) = A163357(A163337(n)) = A163359(A163335(n)). Cf. also A166041.

A163339 Inverse permutation to A163338.

Original entry on oeis.org

1, 2, 4, 8, 5, 3, 6, 9, 13, 18, 24, 31, 23, 17, 12, 7, 11, 16, 22, 29, 37, 47, 38, 30, 39, 48, 58, 70, 59, 49, 60, 71, 83, 97, 84, 72, 61, 51, 42, 33, 41, 50, 40, 32, 25, 19, 14, 10, 15, 20, 26, 34, 27, 21, 28, 35, 43, 53, 44, 36, 45, 54, 64, 75, 87, 100, 86, 74, 63, 52, 62
Offset: 1

Views

Author

Antti Karttunen, Jul 29 2009

Keywords

Crossrefs

Inverse: A163338.

Formula

a(n) = A163335(n-1) + 1.
Showing 1-7 of 7 results.