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 1-3 of 3 results.

A233136 Concatenated shortest (x+1,2x)-codes for the positive integers.

Original entry on oeis.org

1, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 1, 2, 1, 2, 1, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 2, 2, 2, 1, 2, 2, 1, 2, 2, 1
Offset: 1

Views

Author

Clark Kimberling, Dec 05 2013

Keywords

Comments

Concatenate the representations of the positive integers in A233135, and then separate the digits by commas, in the manner analogous to A030302.

Examples

			A233135 = (1,2,21,22,221,212,...), so that A233136 = (1,2,2,1,2,2,2,2,1,2,1,2,...).
		

Crossrefs

Programs

  • Mathematica
    b[x_] := b[x] = If[OddQ[x], x - 1, x/2]; u[n_] := 2 - Mod[Drop[FixedPointList[b, n], -3], 2]; u[1] = {1}; t = Table[u[n], {n, 1, 30}]; Table[FromDigits[u[n]], {n, 1, 50}]  (* A233137 *)
    Flatten[t]  (* A233138 *)
    Table[FromDigits[Reverse[u[n]]], {n, 1, 30}]  (* A233135 *)
    Flatten[Table[Reverse[u[n]], {n, 1, 30}]]  (* A233136 *)

A233137 Reversed shortest (x+1,2x)-code of n.

Original entry on oeis.org

1, 2, 12, 22, 122, 212, 1212, 222, 1222, 2122, 12122, 2212, 12212, 21212, 121212, 2222, 12222, 21222, 121222, 22122, 122122, 212122, 1212122, 22212, 122212, 212212, 1212212, 221212, 1221212, 2121212, 12121212, 22222, 122222, 212222, 1212222, 221222, 1221222
Offset: 1

Views

Author

Clark Kimberling, Dec 05 2013

Keywords

Comments

(See A233135.)

Crossrefs

Programs

  • Mathematica
    b[x_] := b[x] = If[OddQ[x], x - 1, x/2]; u[n_] := 2 - Mod[Drop[FixedPointList[b, n], -3], 2]; u[1] = {1}; t = Table[u[n], {n, 1, 30}]; Table[FromDigits[u[n]], {n, 1, 50}]  (* A233137 *)
    Flatten[t]  (* A233138 *)
    Table[FromDigits[Reverse[u[n]]], {n, 1, 30}]  (* A233135 *)
    Flatten[Table[Reverse[u[n]], {n, 1, 30}]]  (* A233136 *)

Formula

Define h(x) = x - 1 if x is odd and h(x) = x/2 if x is even, and define H(x,1) = h(x) and H(x,k) = H(H(x,k-1)). For each n > 1, the sequence (H(n,k)) decreases to 1 through two kinds of steps; write 1 when the step is x - 1 and write 2 when the step is x/2. A233137(n) is the concatenation of 1s and 2s, as in the Mathematica program.

A233138 Concatenated reversed shortest (x+1,2x)-codes for the positive integers.

Original entry on oeis.org

1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 1, 2, 2, 1, 2, 2, 2, 1, 2
Offset: 1

Views

Author

Clark Kimberling, Dec 05 2013

Keywords

Comments

Concatenate the representations of the positive integers in A233137, and then separate the digits by commas.

Examples

			A233137 = (1,2,12,22,122,212,...), so that A233138 = (1,2,1,2,2,2,1,2,2,2,1,2,...)
		

Crossrefs

Programs

  • Mathematica
    b[x_] := b[x] = If[OddQ[x], x - 1, x/2]; u[n_] := 2 - Mod[Drop[FixedPointList[b, n], -3], 2]; u[1] = {1}; t = Table[u[n], {n, 1, 30}]; Table[FromDigits[u[n]], {n, 1, 50}]  (* A233137 *)
    Flatten[t]  (* A233138 *)
    Table[FromDigits[Reverse[u[n]]], {n, 1, 30}]  (* A233135 *)
    Flatten[Table[Reverse[u[n]], {n, 1, 30}]]     (* A233136 *)
Showing 1-3 of 3 results.