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.

A287571 Start with 0 and repeatedly substitute 0->0312, 1->3120, 2->1203, 3->2031.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, May 31 2017

Keywords

Comments

This is the fixed point of the morphism 0->0231, 1->2310, 2->3102, 3->1023 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:
0312
0312203131201203
0312203131201203120303122031312020313120120303123120120303122031
		

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0,3,1,2}, 1 -> {3,1,2,0}, 2 -> {1,2,0,3}, 3 -> {2,0,3,1}}] &, {0}, 9];   (* A287571 *)
    Flatten[Position[s, 0]]; (* A287572 *)
    Flatten[Position[s, 1]]; (* A287573 *)
    Flatten[Position[s, 2]]; (* A287574 *)
    Flatten[Position[s, 3]]; (* A287575 *)

Formula

a(n) = 4n - A287574(n) for n >= 1.

A287572 Positions of 0 in A287571.

Original entry on oeis.org

1, 6, 12, 15, 19, 21, 26, 32, 34, 40, 43, 45, 52, 55, 57, 62, 68, 71, 73, 78, 81, 86, 92, 95, 99, 101, 106, 112, 114, 120, 123, 125, 131, 133, 138, 144, 146, 152, 155, 157, 164, 167, 169, 174, 177, 182, 188, 191, 194, 200, 203, 205, 212, 215, 217, 222, 225
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, 2, 0, 1, 1, 3, 2, 0, 2, 0, 1, 3, 0, 1, 3, 2, 0, 1, 3, 2, with
0 in positions given by A287573,
1 in positions given by A287574,
2 in positions given by A287575,
3 in positions given by A287572.

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0,3,1,2}, 1 -> {3,1,2,0}, 2 -> {1,2,0,3}, 3 -> {2,0,3,1}}] &, {0}, 9];   (* A287571 *)
    Flatten[Position[s, 0]]; (* A287572 *)
    Flatten[Position[s, 1]]; (* A287573 *)
    Flatten[Position[s, 2]]; (* A287574 *)
    Flatten[Position[s, 3]]; (* A287575 *)

A287575 Positions of 3 in A287571.

Original entry on oeis.org

2, 7, 9, 16, 20, 22, 27, 29, 35, 37, 44, 46, 49, 56, 58, 63, 65, 72, 74, 79, 82, 87, 89, 96, 100, 102, 107, 109, 115, 117, 124, 126, 132, 134, 139, 141, 147, 149, 156, 158, 161, 168, 170, 175, 178, 183, 185, 192, 195, 197, 204, 206, 209, 216, 218, 223, 226
Offset: 1

Views

Author

Clark Kimberling, Jun 01 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 2, 1, 3, 0, 0, 2, 1, 3, 1, 3, 0, 2, 3, 0, 2, 1, 3, 0, 2, 1, with
0 in positions given by A287574,
1 in positions given by A287575,
2 in positions given by A287572,
3 in positions given by A287573.

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0,3,1,2}, 1 -> {3,1,2,0}, 2 -> {1,2,0,3}, 3 -> {2,0,3,1}}] &, {0}, 9];   (* A287571 *)
    Flatten[Position[s, 0]]; (* A287572 *)
    Flatten[Position[s, 1]]; (* A287573 *)
    Flatten[Position[s, 2]]; (* A287574 *)
    Flatten[Position[s, 3]]; (* A287575 *)

A287573 Positions of 1 in A287571.

Original entry on oeis.org

3, 8, 10, 13, 17, 23, 28, 30, 36, 38, 41, 47, 50, 53, 59, 64, 66, 69, 75, 80, 83, 88, 90, 93, 97, 103, 108, 110, 116, 118, 121, 127, 129, 135, 140, 142, 148, 150, 153, 159, 162, 165, 171, 176, 179, 184, 186, 189, 196, 198, 201, 207, 210, 213, 219, 224, 227
Offset: 1

Views

Author

Clark Kimberling, Jun 01 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 1, 0, 2, 3, 3, 1, 0, 2, 0, 2, 3, 1, 2, 3, 1, 0, 2, 3, 1, 0, with
0 in positions given by A287575,
1 in positions given by A287572,
2 in positions given by A287573,
3 in positions given by A287574.

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0,3,1,2}, 1 -> {3,1,2,0}, 2 -> {1,2,0,3}, 3 -> {2,0,3,1}}] &, {0}, 9]; (* A287571 *)
    Flatten[Position[s, 0]]; (* A287572 *)
    Flatten[Position[s, 1]]; (* A287573 *)
    Flatten[Position[s, 2]]; (* A287574 *)
    Flatten[Position[s, 3]]; (* A287575 *)
Showing 1-4 of 4 results.