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.

A248514 Fractal sequence of the dispersion of the "odious numbers".

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 4, 2, 1, 5, 6, 3, 7, 4, 2, 8, 1, 9, 10, 5, 11, 6, 3, 12, 13, 7, 4, 14, 2, 15, 16, 8, 1, 17, 18, 9, 19, 10, 5, 20, 21, 11, 6, 22, 3, 23, 24, 12, 25, 13, 7, 26, 4, 27, 28, 14, 2, 29, 30, 15, 31, 16, 8, 32, 1, 33, 34, 17, 35, 18, 9, 36, 37, 19
Offset: 1

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Author

Clark Kimberling, Oct 08 2014

Keywords

Comments

As a fractal sequence, it contains infinitely many copies of itself: removing the first occurrence of each number leaves the original sequence.

Examples

			A northwest corner of the dispersion (A248513) of the "odious numbers" (A181155) follows:
1 ... 2 ... 3 ... 5 ... 9 ... 17 .... 33
4 ... 8 ... 15 .. 29 .. 57 .. 113 ... 225
6 ... 12 .. 23 .. 45 .. 89 .. 177 ... 353
7 ... 14 .. 27 .. 53 .. 105 .. 209 .. 417
10 .. 20 .. 39 .. 77 .. 153 .. 305 .. 609
The numbers 1, 2, 3, 4, 5 appear in rows 1, 1, 1, 2, 1, respectively, so that A248514 = (1, 1, 1, 2, 1, ...).
		

References

  • Clark Kimberling, "Fractal sequences and interspersions," Ars Combinatoria 45 (1997) 157-168.

Crossrefs

Cf. A248513.

Programs

  • Mathematica
    r = 40; r1 = 10; (* r = # rows of T, r1 = # rows to show*);
    c = 40; c1 = 12; (* c = # cols of T, c1 = # cols to show*);
    x = GoldenRatio; s[n_] := s[n] = If[n < 1, 0, 2 n - Mod[Total[IntegerDigits[n - 1, 2]], 2]];
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1,   Length[Union[list]]]; rows = {NestList[s, 1, c]};
    Do[rows = Append[rows, NestList[s, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]]; TableForm[Table[t[i, j], {i, 1, r1}, {j, 1, c1}]] (* A248513 array*)
    u = Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]]  (* A248013 sequence*)
    row[i_] := row[i] = Table[t[i, j], {j, 1, c}]
    f[n_] := Select[Range[r], MemberQ[row[#], n] &]
    v = Flatten[Table[f[n], {n, 1, 200}]]  (* A248514 *)