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.

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A244690 The spiral of Champernowne read by the South-Southeast ray.

Original entry on oeis.org

1, 1, 4, 8, 1, 1, 2, 4, 3, 4, 3, 7, 8, 8, 0, 1, 9, 6, 6, 1, 2, 7, 2, 2, 3, 2, 0, 3, 2, 9, 9, 4, 9, 9, 9, 5, 4, 1, 1, 6, 7, 7, 4, 7, 8, 5, 8, 9, 7, 6, 0, 6, 7, 1, 1, 1, 5, 8, 3, 1, 3, 4, 9, 5, 1, 5, 3, 0, 7, 1, 8, 2, 1, 9, 1, 0, 1, 2, 1, 2, 2, 0, 3, 4, 2, 5, 9, 4, 7, 2, 8, 8, 5, 0, 3, 1, 7, 6, 3, 3, 4, 6, 7, 6, 3
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 16n^2 - 25n + 10 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.

A244692 The spiral of Champernowne read by the East-Southeast ray.

Original entry on oeis.org

1, 1, 0, 6, 1, 8, 2, 2, 9, 4, 5, 6, 7, 9, 0, 5, 3, 1, 5, 8, 2, 2, 1, 5, 9, 2, 9, 4, 4, 3, 8, 6, 7, 4, 8, 1, 8, 5, 9, 9, 7, 6, 2, 9, 4, 8, 6, 3, 9, 9, 0, 1, 0, 6, 7, 1, 1, 2, 5, 8, 3, 1, 4, 4, 9, 5, 1, 6, 3, 0, 7, 1, 8, 2, 1, 0, 2, 1, 1, 2, 2, 2, 3, 0, 3, 5, 2, 6, 9, 4, 8, 2, 9, 8, 5, 0, 3, 2, 7, 6, 4, 3, 5, 6, 7
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 16n^2 - 39n + 24 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.

A033990 Write 0,1,2,... in a clockwise spiral on a square lattice, writing each digit at a separate lattice point, starting with 0 at the origin and 1 at x=0, y=-1; sequence gives the numbers on the negative y-axis.

Original entry on oeis.org

0, 1, 1, 8, 3, 7, 6, 2, 1, 5, 1, 1, 6, 2, 2, 1, 3, 4, 0, 4, 5, 3, 6, 7, 0, 8, 9, 1, 4, 6, 1, 2, 7, 1, 1, 4, 4, 8, 1, 7, 4, 7, 2, 0, 8, 8, 2, 4, 4, 1, 2, 8, 4, 6, 3, 2, 7, 3, 3, 7, 3, 2, 4, 1, 2, 3, 4, 7, 5, 6, 5, 2, 0, 1, 5, 8, 9, 8, 6, 4, 1, 7, 6, 1, 7, 8, 7, 7, 5, 1, 8, 4, 7, 6, 9, 2, 2, 3, 9, 0, 1, 0, 1, 6, 8
Offset: 0

Views

Author

Keywords

Comments

Consider array of digits 0_(1)23456789(1)0111213141516171(8)1920212223...; in this array add to n-th pointer 8*n+1 to get next pointer. E.g., n=1 so n+(8*1+1)=10 -> n=10 so n+(8*2+1)=27 -> n=27 so ... etc. - comment from Patrick De Geest.

Examples

			The spiral begins
                 2---3---2---4---2---5---2
                 |                       |
                 2   1---3---1---4---1   6
                 |   |               |   |
                 2   2   4---5---6   5   2
                 |   |   |       |   |   |
                 1   1   3   0   7   1   7
                 |   |   |   |   |   |   |
                 2   1   2---1   8   6   2
                 |   |           |   |   |
                 0   1---0---1---9   1   8
                 |                   |   |
                 2---9---1---8---1---7   2
                                         |
                             3---0---3---9
.
We begin with the 0 and wrap the numbers 1 2 3 4 ... around it. Then the sequence is obtained by reading downwards, starting from the initial 0. - _Andrew Woods_, May 20 2012
		

Crossrefs

Sequences based on the same spiral: A033953, A033988, A033989. Spiral without zero: A033952.
Other sequences from spirals: A001107, A002939, A007742, A033951, A033954, A033991, A002943, A033996, A033988.

Programs

Formula

a(n) = A033307(4*n^2-3*n-1) for n > 0. - Andrew Woods, May 20 2012

Extensions

More terms from Patrick De Geest, Oct 15 1999
Edited by Charles R Greathouse IV, Nov 01 2009

A033953 Write 0,1,2,... in a clockwise spiral on a square lattice, writing each digit at a separate lattice point, starting with 0 at the origin and 1 at x=0, y=-1; sequence gives the numbers on the positive x-axis.

Original entry on oeis.org

0, 7, 1, 7, 4, 2, 8, 1, 1, 3, 1, 2, 0, 2, 3, 1, 3, 4, 6, 5, 5, 5, 7, 7, 8, 8, 9, 6, 8, 1, 1, 1, 2, 3, 1, 8, 0, 6, 1, 7, 0, 9, 2, 8, 4, 3, 2, 1, 1, 7, 2, 6, 2, 1, 3, 3, 5, 5, 3, 2, 2, 0, 4, 3, 2, 5, 4, 6, 5, 0, 5, 1, 1, 6, 5, 8, 1, 2, 6, 7, 3, 8, 7, 8, 9, 5, 7, 1, 8, 2, 8, 6, 1, 9, 9, 3, 6, 7, 9, 0, 1, 4, 6, 1, 0
Offset: 0

Views

Author

Keywords

Examples

			  2---3---2---4---2---5---2
  |                       |
  2   1---3---1---4---1   6
  |   |               |   |
  2   2   4---5---6   5   2
  |   |   |       |   |   |
  1   1   3   0   7   1   7
  |   |   |   |   |   |   |
  2   1   2---1   8   6   2
  |   |           |   |   |
  0   1---0---1---9   1   8
  |                   |   |
  2---9---1---8---1---7   2
We begin with the 0 and wrap the numbers 1 2 3 4 ... around it. Then the sequence is obtained by reading rightwards, starting from the initial 0. - _Andrew Woods_, May 20 2012
		

Crossrefs

Sequences based on the same spiral: A033988, A033989, A033990. Spiral without zero: A033952.
Other sequences from spirals: A001107, A002939, A007742, A033951, A033954, A033991, A002943, A033996, A033988.

Programs

Formula

a(n) = A033307(4*n^2 + 3*n - 1) for n > 0. - Andrew Woods, May 20 2012

Extensions

More terms from Andrew J. Gacek (andrew(AT)dgi.net)
Edited by Charles R Greathouse IV, Nov 01 2009

A244691 The spiral of Champernowne read by the Southeast ray.

Original entry on oeis.org

1, 9, 7, 9, 5, 5, 9, 1, 1, 1, 3, 2, 2, 9, 3, 3, 9, 4, 4, 3, 5, 6, 1, 7, 8, 3, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 7, 7, 9, 3, 9, 0, 0, 3, 1, 1, 0
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 4n^2 - 4n + 1 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.

A244678 The spiral of Champernowne read by the East-Northeast ray.

Original entry on oeis.org

1, 1, 2, 7, 5, 1, 2, 6, 3, 4, 3, 6, 7, 6, 0, 1, 1, 1, 5, 1, 2, 1, 1, 2, 1, 4, 9, 3, 8, 0, 8, 4, 3, 9, 8, 5, 6, 0, 0, 6, 7, 5, 2, 7, 6, 2, 6, 9, 3, 2, 0, 4, 1, 1, 4, 1, 2, 1, 1, 3, 3, 0, 1, 1, 2, 5, 0, 1, 1, 3, 7, 2, 1, 1, 6, 0, 6, 2, 2, 1, 2, 1, 2, 2, 7, 5, 8, 2, 2, 4, 8, 6, 2, 2, 4, 1, 6, 3, 3, 4, 4, 7, 3, 3, 7
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 16n^2 - 37n + 22 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.

A244687 The spiral of Champernowne read by the Southwest ray.

Original entry on oeis.org

1, 7, 5, 6, 1, 0, 3, 1, 7, 1, 1, 5, 2, 2, 7, 3, 3, 3, 4, 5, 3, 6, 6, 7, 8, 8, 5, 0, 5, 1, 2, 2, 7, 3, 0, 5, 1, 6, 0, 8, 7, 9, 2, 1, 5, 3, 6, 5, 5, 7, 2, 9, 7, 1, 0, 3, 1, 5, 0, 7, 7, 0, 2, 2, 5, 5, 6, 8, 5, 0, 2, 3, 7, 6, 0, 9, 1, 2, 0, 5, 7, 8, 2, 2, 5, 5, 6, 8, 5, 2, 2, 6, 7, 9, 0, 3, 1, 7, 0, 0, 0, 4, 0, 5, 1
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 4n^2 - 6n + 3 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.

A244679 The spiral of Champernowne read by the Northeast ray.

Original entry on oeis.org

1, 3, 1, 0, 3, 0, 1, 6, 1, 1, 3, 1, 2, 3, 2, 3, 7, 4, 4, 5, 5, 6, 7, 7, 7, 3, 9, 9, 7, 1, 2, 2, 5, 3, 6, 4, 5, 6, 2, 7, 7, 9, 0, 1, 1, 2, 0, 4, 7, 6, 2, 8, 5, 0, 6, 2, 5, 4, 2, 7, 7, 9, 0, 2, 1, 4, 0, 7, 7, 0, 2, 2, 5, 5, 6, 8, 5, 1, 2, 4, 7, 7, 0, 1, 1, 4, 0, 8, 7, 1, 2, 5, 5, 8, 6, 2, 5, 6, 2, 0, 0, 4, 0, 0, 8
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 4n^2 - 10n + 7 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.

A244680 The spiral of Champernowne read by the North-Northeast ray.

Original entry on oeis.org

1, 1, 4, 7, 1, 6, 2, 9, 7, 4, 6, 7, 7, 2, 0, 6, 9, 1, 5, 0, 2, 2, 1, 7, 3, 2, 9, 7, 2, 3, 8, 9, 9, 4, 8, 5, 4, 5, 0, 3, 7, 6, 3, 4, 8, 8, 7, 7, 7, 9, 0, 4, 3, 1, 1, 1, 3, 4, 2, 1, 3, 2, 5, 4, 1, 5, 1, 6, 6, 1, 7, 0, 7, 9, 1, 0, 9, 8, 1, 2, 2, 8, 9, 4, 2, 5, 7, 0, 6, 2, 8, 6, 1, 9, 3, 1, 5, 2, 2, 3, 4, 4, 3, 6, 3
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 16n^2 - 35n + 20 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.

A244681 The spiral of Champernowne read by the North ray.

Original entry on oeis.org

1, 4, 2, 2, 5, 5, 4, 1, 9, 1, 1, 4, 2, 2, 3, 3, 3, 6, 4, 5, 3, 6, 6, 4, 7, 8, 9, 1, 4, 1, 1, 1, 3, 5, 4, 1, 4, 3, 7, 1, 7, 4, 0, 2, 2, 9, 3, 2, 9, 6, 7, 2, 8, 7, 1, 3, 9, 1, 6, 3, 2, 8, 1, 4, 7, 8, 6, 4, 4, 2, 1, 5, 3, 8, 7, 5, 4, 8, 3, 6, 7, 1, 9, 7, 2, 8, 6, 7, 9, 7, 3, 8, 8, 0, 0, 9, 9, 6, 8, 0, 0, 2, 1, 8, 0
Offset: 1

Views

Author

Robert G. Wilson v, Jul 04 2014

Keywords

Examples

			See A244677 for the spiral of David Gawen Champernowne.
		

Crossrefs

Programs

  • Mathematica
    almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 4n^2 - 9n + 6 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]

Formula

See A244677 formula section.
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