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 1-4 of 4 results.

A287561 Start with 0 and repeatedly substitute 0->0213, 1->2130, 2->1302, 3->3021.

Original entry on oeis.org

0, 2, 1, 3, 1, 3, 0, 2, 2, 1, 3, 0, 3, 0, 2, 1, 2, 1, 3, 0, 3, 0, 2, 1, 0, 2, 1, 3, 1, 3, 0, 2, 1, 3, 0, 2, 2, 1, 3, 0, 3, 0, 2, 1, 0, 2, 1, 3, 3, 0, 2, 1, 0, 2, 1, 3, 1, 3, 0, 2, 2, 1, 3, 0, 1, 3, 0, 2, 2, 1, 3, 0, 3, 0, 2, 1, 0, 2, 1, 3, 3, 0, 2, 1, 0, 2
Offset: 1

Views

Author

Clark Kimberling, May 31 2017

Keywords

Comments

This is the fixed point of the morphism 0->0213, 1->2130, 2->1302, 3->3021 starting with 0. Let t be the (nonperiodic) sequence of positions of 0, and likewise, u for 1, v for 2, and w for 3; then t(n)/n -> 4, u(n)/n -> 4, v(n)/n -> 4, w(n)/n -> 4. Also, t(n) + u(n) + v(n) + w(n) = 16*n - 6 for n >= 1. See A287556 for a guide to related sequences.

Examples

			First three iterations of the morphism:
0213
0213130221303021
0213130221303021213030210213130213022130302102133021021313022130
		

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0, 2, 1, 3}, 1 -> {2, 1, 3, 0}, 2 -> {1, 3, 0, 2}, 3 -> {3, 0, 2, 1}}] &, {0}, 9];   (* A287561 *)
    Flatten[Position[s, 0]]; (* A287562 *)
    Flatten[Position[s, 1]]; (* A287563 *)
    Flatten[Position[s, 2]]; (* A287564 *)
    Flatten[Position[s, 3]]; (* A287565 *)

Formula

a(n) = 4n - A287565(n) for n >= 1.

A287562 Positions of 0 in A287561.

Original entry on oeis.org

1, 7, 12, 14, 20, 22, 25, 31, 35, 40, 42, 45, 50, 53, 59, 64, 67, 72, 74, 77, 82, 85, 91, 96, 97, 103, 108, 110, 116, 118, 121, 127, 132, 134, 137, 143, 147, 152, 154, 157, 162, 165, 171, 176, 177, 183, 188, 190, 194, 197, 203, 208, 209, 215, 220, 222, 228
Offset: 1

Views

Author

Clark Kimberling, May 31 2017

Keywords

Comments

a(n) - a(n-1) is in {1,2,3,4,5,6,7} for n >= 1; also, 4n - a(n) is in {0,1,2,3} for n >= 1. The first 20 numbers 4n - a(n) are 3, 1, 0, 2, 0, 2, 3, 1, 1, 0, 2, 3, 2, 3, 1, 0, 1, 0, 2, 3, with
0 in positions given by A287563,
1 in positions given by A287564,
2 in positions given by A287565,
3 in positions given by A287562.

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0, 2, 1, 3}, 1 -> {2, 1, 3, 0}, 2 -> {1, 3, 0, 2}, 3 -> {3, 0, 2, 1}}] &, {0}, 9];   (* A287561 *)
    Flatten[Position[s, 0]]; (* A287562 *)
    Flatten[Position[s, 1]]; (* A287563 *)
    Flatten[Position[s, 2]]; (* A287564 *)
    Flatten[Position[s, 3]]; (* A287565 *)

A287565 Positions of 3 in A287561.

Original entry on oeis.org

4, 6, 11, 13, 19, 21, 28, 30, 34, 39, 41, 48, 49, 56, 58, 63, 66, 71, 73, 80, 81, 88, 90, 95, 100, 102, 107, 109, 115, 117, 124, 126, 131, 133, 140, 142, 146, 151, 153, 160, 161, 168, 170, 175, 180, 182, 187, 189, 193, 200, 202, 207, 212, 214, 219, 221, 227
Offset: 1

Views

Author

Clark Kimberling, May 31 2017

Keywords

Comments

a(n) - a(n-1) is in {1,2,3,4,5,6,7} for n >= 1; also, 4n - a(n) is in {0,1,2,3} for n >= 1. The first 20 numbers 4n - a(n) are 0, 2, 1, 3, 1, 3, 0, 2, 2, 1, 3, 0, 3, 0, 2, 1, 2, 1, 3, 0, with
0 in positions given by A287562,
1 in positions given by A287563,
2 in positions given by A287564,
3 in positions given by A287565.

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0, 2, 1, 3}, 1 -> {2, 1, 3, 0}, 2 -> {1, 3, 0, 2}, 3 -> {3, 0, 2, 1}}] &, {0}, 9];   (* A287561 *)
    Flatten[Position[s, 0]]; (* A287562 *)
    Flatten[Position[s, 1]]; (* A287563 *)
    Flatten[Position[s, 2]]; (* A287564 *)
    Flatten[Position[s, 3]]; (* A287565 *)

Formula

a(n) = 4n - A287561(n) for n >= 1.

A287563 Positions of 1 in A287561.

Original entry on oeis.org

3, 5, 10, 16, 18, 24, 27, 29, 33, 38, 44, 47, 52, 55, 57, 62, 65, 70, 76, 79, 84, 87, 89, 94, 99, 101, 106, 112, 114, 120, 123, 125, 130, 136, 139, 141, 145, 150, 156, 159, 164, 167, 169, 174, 179, 181, 186, 192, 196, 199, 201, 206, 211, 213, 218, 224, 226
Offset: 1

Views

Author

Clark Kimberling, May 31 2017

Keywords

Comments

a(n) - a(n-1) is in {1,2,3,4,5,6} for n >= 1; also, 4n - a(n) is in {0,1,2,3} for n >= 1. The first 20 numbers 4n - a(n) are 1, 3, 2, 0, 2, 0, 1, 3, 3, 2, 0, 1, 0, 1, 3, 2, 3, 2, 0, 1, with
0 in positions given by A287565,
1 in positions given by A287562,
2 in positions given by A287563,
3 in positions given by A287564.

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0, 2, 1, 3}, 1 -> {2, 1, 3, 0}, 2 -> {1, 3, 0, 2}, 3 -> {3, 0, 2, 1}}] &, {0}, 9];   (* A287561 *)
    Flatten[Position[s, 0]]; (* A287562 *)
    Flatten[Position[s, 1]]; (* A287563 *)
    Flatten[Position[s, 2]]; (* A287564 *)
    Flatten[Position[s, 3]]; (* A287565 *)
Showing 1-4 of 4 results.