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.

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A194983 Fractalization of (1+[n/sqrt(5)]), where [ ]=floor.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Sep 07 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. The sequence (1+[n/sqrt(5)]) is A194964.

Crossrefs

Programs

  • Mathematica
    r = Sqrt[5]; p[n_] := 1 + Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194964 *)
    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] (* A194983 *)
    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}]]  (* A194984 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]  (* A194985 *)

A194984 Interspersion fractally induced by A194964, a rectangular array, by antidiagonals.

Original entry on oeis.org

1, 3, 2, 6, 4, 5, 10, 7, 9, 8, 15, 11, 14, 12, 13, 21, 16, 20, 17, 19, 18, 28, 22, 27, 23, 26, 24, 25, 36, 29, 35, 30, 34, 31, 33, 32, 45, 37, 44, 38, 43, 39, 42, 40, 41, 55, 46, 54, 47, 53, 48, 52, 49, 51, 50, 66, 56, 65, 57, 64, 58, 63, 59, 62, 61, 60, 78, 67, 77
Offset: 1

Views

Author

Clark Kimberling, Sep 07 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. Every pair of rows eventually intersperse. As a sequence, A194984 is a permutation of the positive integers, with inverse A194985.

Examples

			Northwest corner:
1...3...6...10..15..21..28
2...4...7...11..16..22..29
5...9...14..20..27..35..44
8...12..17..23..30..38..47
13..19..26..34..43..53..64
		

Crossrefs

Programs

  • Mathematica
    r = Sqrt[5]; p[n_] := 1 + Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194964 *)
    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] (* A194983 *)
    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}]]  (* A194984 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]  (* A194985 *)

A194987 Fractalization of (1+[n/sqrt(6)]), where [ ]=floor.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Sep 07 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. The sequence (1+[n/sqrt(6)]) is A194986.

Crossrefs

Programs

  • Mathematica
    r = Sqrt[6]; p[n_] := 1 + Floor[n/r]
    Table[p[n], {n, 1, 90}] (* A194986 *)
    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] (* A194987 *)
    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}]] (* A194988 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]  (* A194989 *)

A194989 Inverse permutation of A194988; every positive integer occurs exactly once.

Original entry on oeis.org

1, 3, 2, 5, 6, 4, 8, 10, 9, 7, 12, 14, 15, 13, 11, 17, 19, 21, 20, 18, 16, 23, 25, 28, 27, 26, 24, 22, 30, 32, 35, 36, 34, 33, 31, 29, 38, 40, 43, 45, 44, 42, 41, 39, 37, 47, 49, 52, 54, 55, 53, 51, 50, 48, 46, 57, 59, 62, 64, 66, 65, 63, 61, 60, 58, 56, 68, 70, 73
Offset: 1

Views

Author

Clark Kimberling, Sep 07 2011

Keywords

Crossrefs

Programs

A330081 If the binary expansion of n is (b(1), ..., b(w)), then the binary expansion of a(n) is (b(1), b(3), b(5), ..., b(6), b(4), b(2)).

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 5, 7, 8, 10, 12, 14, 9, 11, 13, 15, 16, 20, 18, 22, 24, 28, 26, 30, 17, 21, 19, 23, 25, 29, 27, 31, 32, 36, 40, 44, 34, 38, 42, 46, 48, 52, 56, 60, 50, 54, 58, 62, 33, 37, 41, 45, 35, 39, 43, 47, 49, 53, 57, 61, 51, 55, 59, 63, 64, 72, 68, 76
Offset: 0

Views

Author

Rémy Sigrist, Dec 01 2019

Keywords

Comments

This sequence is a permutation of the nonnegative integers that preserves the binary length as well as the Hamming weight. See A330090 for the inverse.

Examples

			For n = 1234:
- the binary expansion of 1234 is "10011010010",
- odd-indexed bits are "101100",
- even-indexed bits are "01001", and in reverse order "10010",
- hence the binary expansion of a(1234) is "10110010010",
- so a(1234) = 1426.
		

Crossrefs

See A329303 for a similar sequence.
Cf. A003558, A194959, A330090 (inverse).

Programs

  • PARI
    shuffle(v) = { my (w=vector(#v), o=0, e=#v+1); for (k=1, #v, w[if (k%2, o++, e--)]=v[k]); w }
    a(n) = fromdigits(shuffle(binary(n)), 2)

Formula

If n has w binary digits, then a^A003558(w-1)(n) = n (where a^k denotes the k-th iterate of the sequence).

A194915 Interspersion fractally induced by A194990, a rectangular array, by antidiagonals.

Original entry on oeis.org

1, 3, 2, 6, 4, 5, 10, 7, 9, 8, 15, 11, 14, 13, 12, 21, 16, 20, 19, 17, 18, 28, 22, 27, 26, 23, 25, 24, 36, 29, 35, 34, 30, 33, 32, 31, 45, 37, 44, 43, 38, 42, 41, 39, 40, 55, 46, 54, 53, 47, 52, 51, 48, 50, 49, 66, 56, 65, 64, 57, 63, 62, 58, 61, 60, 59, 78, 67, 77
Offset: 1

Views

Author

Clark Kimberling, Sep 08 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. Every pair of rows eventually intersperse. As a sequence, A194915 is a permutation of the positive integers, with inverse A194916.

Examples

			Northwest corner:
1...3...6...10..15..21
2...4...7...11..16..22
5...9...14..20..27..35
8...13..19..26..34..43
12..17..23..30..38..47
		

Crossrefs

Programs

  • Mathematica
    r = Sqrt[8]; p[n_] := 1 + Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194990  *)
    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] (* A194914 *)
    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}]]  (* A194915 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]  (* A194916 *)

A194921 Fractalization of (n - [n/sqrt(2)]), where [ ]=floor.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Sep 08 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. The sequence (n-[n/sqrt(2)]) is A194920.

Crossrefs

Programs

  • Mathematica
    r = Sqrt[2]; p[n_] := n - Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194920 *)
    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]  (* A194921 *)
    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}]]  (* A194922 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]   (* A195071 *)

A194922 Interspersion fractally induced by A194920, a rectangular array, by antidiagonals.

Original entry on oeis.org

1, 3, 2, 6, 5, 4, 10, 9, 7, 8, 15, 14, 11, 13, 12, 21, 20, 16, 19, 18, 17, 28, 27, 22, 26, 25, 23, 24, 36, 35, 29, 34, 33, 30, 32, 31, 45, 44, 37, 43, 42, 38, 41, 40, 39, 55, 54, 46, 53, 52, 47, 51, 50, 49, 48, 66, 65, 56, 64, 63, 57, 62, 61, 60, 58, 59, 78, 77, 67
Offset: 1

Views

Author

Clark Kimberling, Sep 08 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. Every pair of rows eventually intersperse. As a sequence, A194922 is a permutation of the positive integers, with inverse A195071.

Examples

			Northwest corner:
   1,  3,  6, 10, 15, 21
   2,  5,  9, 14, 20, 27, 35
   4,  7, 11, 16, 22, 29, 37
   8, 13, 19, 26, 34, 43, 53
  12, 18, 25, 33, 42, 52, 63
		

Crossrefs

Programs

  • Mathematica
    r = Sqrt[2]; p[n_] := n - Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A194920 *)
    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]  (* A194921 *)
    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}]]  (* A194922 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]   (* A195071 *)

A194966 Interspersion fractally induced by A194965, a rectangular array, by antidiagonals.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 19, 20, 21, 17, 22, 25, 26, 27, 28, 23, 24, 29, 33, 34, 35, 36, 30, 31, 32, 37, 42, 43, 44, 45, 38, 39, 40, 41, 46, 52, 53, 54, 55, 47, 48, 49, 50, 51, 56, 63, 64, 65, 66, 57, 59, 60, 61, 62, 58, 67, 75, 76
Offset: 1

Views

Author

Clark Kimberling, Sep 07 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. Every pair of rows eventually intersperse. As a sequence, A194966 is a permutation of the positive integers, with inverse A194967.

Examples

			Northwest corner:
1...2...4...7...11..16
3...5...8...12..18..25
6...9...13..19..26..34
10..14..20..27..35..44
15..21..28..36..45..55
		

Crossrefs

Cf. A194959, A194965, A194967 (inverse).

Programs

  • Mathematica
    p[n_] := Floor[(n + 4)/5] + Mod[n - 1, 5]
    Table[p[n], {n, 1, 90}]  (* A053824(n+5), n>=0 *)
    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]   (* A194965 *)
    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}]]  (* A194966 *)
    q[n_] := Position[w, n]; Flatten[
    Table[q[n], {n, 1, 80}]]  (* A194967 *)

A194969 Interspersion fractally induced by A194968, a rectangular array, by antidiagonals.

Original entry on oeis.org

1, 2, 3, 4, 6, 5, 7, 10, 8, 9, 11, 15, 12, 13, 14, 16, 21, 17, 18, 20, 19, 22, 28, 23, 24, 27, 25, 26, 29, 36, 30, 31, 35, 32, 34, 33, 37, 45, 38, 39, 44, 40, 43, 41, 42, 46, 55, 47, 48, 54, 49, 53, 50, 51, 52, 56, 66, 57, 58, 65, 59, 64, 60, 61, 63, 62, 67, 78, 68
Offset: 1

Views

Author

Clark Kimberling, Sep 07 2011

Keywords

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. Every pair of rows eventually intersperse. As a sequence, A194969 is a permutation of the positive integers, with inverse A194970.

Examples

			Northwest corner:
1...2...4...7...11..16
3...6...10..15..21..28
5...8...12..17..23..30
9...13..18..24..31..39
14..20..27..35..44..54
		

Crossrefs

Cf. A194958, A019446, A194968, A194970 (inverse).

Programs

  • Mathematica
    r = GoldenRatio; p[n_] := 1 + Floor[n/r]
    Table[p[n], {n, 1, 90}]  (* A019446 *)
    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]  (* A194968 *)
    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}]]  (* A194969 *)
    q[n_] := Position[w, n]; Flatten[Table[q[n],
    {n, 1, 80}]]  (* A194970 *)
Previous Showing 11-20 of 61 results. Next