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.

A194109 Inverse permutation of A194108; every positive integer occurs exactly once.

Original entry on oeis.org

1, 3, 6, 2, 5, 9, 10, 15, 4, 8, 13, 14, 20, 21, 7, 12, 18, 19, 26, 27, 28, 36, 11, 17, 24, 25, 33, 34, 35, 44, 45, 55, 16, 23, 31, 32, 41, 42, 43, 53, 54, 65, 66, 78, 22, 30, 39, 40, 50, 51, 52, 63, 64, 76, 77, 90, 91, 29, 38, 48, 49, 60, 61, 62, 74, 75, 88, 89, 103
Offset: 1

Views

Author

Clark Kimberling, Aug 15 2011

Keywords

Crossrefs

Cf. A194108.

Programs

A194106 Sum{floor(j*sqrt(3)) : 1<=j<=n}; n-th partial sum of Beatty sequence for sqrt(3).

Original entry on oeis.org

1, 4, 9, 15, 23, 33, 45, 58, 73, 90, 109, 129, 151, 175, 200, 227, 256, 287, 319, 353, 389, 427, 466, 507, 550, 595, 641, 689, 739, 790, 843, 898, 955, 1013, 1073, 1135, 1199, 1264, 1331, 1400, 1471, 1543, 1617, 1693, 1770, 1849, 1930, 2013, 2097
Offset: 1

Views

Author

Clark Kimberling, Aug 15 2011

Keywords

Crossrefs

Cf. A194107, A194108, A194109, A022838 (Beatty sequence for sqrt(3)).

Programs

  • Mathematica
    c[n_] := Sum[Floor[j*Sqrt[3]], {j, 1, n}];
    c = Table[c[n], {n, 1, 90}]

A194107 Natural fractal sequence of A194106.

Original entry on oeis.org

1, 2, 3, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17
Offset: 1

Views

Author

Clark Kimberling, Aug 15 2011

Keywords

Comments

See A194029 for definitions of natural fractal sequence and natural interspersion.

Crossrefs

Programs

  • Mathematica
    z = 40; g = Sqrt[3];
    c[k_] := Sum[Floor[j*g], {j, 1, k}];
    c = Table[c[k], {k, 1, z}]  (* A194106 *)
    f[n_] := If[MemberQ[c, n], 1, 1 + f[n - 1]]
    f = Table[f[n], {n, 1, 800}]  (* A194107 *)
    r[n_] := Flatten[Position[f, n]]
    t[n_, k_] := r[n][[k]]
    TableForm[Table[t[n, k], {n, 1, 8}, {k, 1, 7}]]
    p = Flatten[Table[t[k, n - k + 1], {n, 1, 16}, {k, 1, n}]]  (* A194108 *)
    q[n_] := Position[p, n]; Flatten[Table[q[n], {n, 1, 80}]]  (* A194109 *)

A195108 Interspersion fractally induced by A004736.

Original entry on oeis.org

1, 2, 3, 5, 6, 4, 8, 10, 7, 9, 13, 15, 11, 14, 12, 19, 21, 17, 20, 18, 16, 26, 28, 23, 27, 24, 22, 25, 34, 36, 30, 35, 32, 29, 33, 31, 43, 45, 39, 44, 41, 37, 42, 40, 38, 53, 55, 49, 54, 51, 47, 52, 50, 48, 46, 64, 66, 59, 65, 62, 57, 63, 61, 58, 56, 60, 76, 78, 71
Offset: 1

Views

Author

Clark Kimberling, Sep 09 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence.
The sequence A004736 is the fractal sequence obtained by concatenating the segments 1; 2,1; 3,2,1; 4,3,2,1;...
Every pair of rows of A195108 eventually intersperse.
As a sequence, A194108 is a permutation of the positive integers, with inverse A195109.

Examples

			Northwest corner:
1...2...5...8...13..19..26
3...6...10..15..21..28..36
4...7...11..17..23..30..39
9...14..20..27..35..44..54
12..18..24..32..41..51..62
		

Crossrefs

Programs

  • Mathematica
    j[n_] := Table[n + 1 - k, {k, 1, n}]; t[1] = j[1];
    t[n_] := Join[t[n - 1], j[n]]   (* A004736 *)
    t[10]
    p[n_] := t[20][[n]]
    g[1] = {1}; g[n_] := Insert[g[n - 1], n, p[n]]
    f[1] = g[1]; f[n_] := Join[f[n - 1], g[n]]
    f[20] (* A195107 *)
    row[n_] := Position[f[30], n];
    u = TableForm[Table[row[n], {n, 1, 5}]]
    v[n_, k_] := Part[row[n], k];
    w = Flatten[Table[v[k, n - k + 1], {n, 1, 13},
    {k, 1, n}]] (* A195108 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]] (* A195109 *)
Showing 1-4 of 4 results.