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.

A360434 a(n) is the greatest number k not yet in the sequence such that A022290(n) = A022290(k).

Original entry on oeis.org

0, 1, 2, 4, 3, 5, 8, 9, 6, 7, 10, 16, 12, 17, 18, 20, 11, 13, 14, 19, 15, 21, 32, 33, 24, 25, 34, 36, 35, 37, 40, 41, 22, 23, 26, 28, 27, 29, 38, 39, 30, 31, 42, 64, 48, 65, 66, 68, 44, 49, 50, 67, 52, 69, 72, 73, 70, 71, 74, 80, 76, 81, 82, 84, 43, 45, 46, 51
Offset: 0

Views

Author

Rémy Sigrist, Feb 07 2023

Keywords

Comments

This sequence is a self-inverse permutation of the nonnegative integers.

Examples

			There are three numbers k such that A022290(k) = 11: 15, 19, 20,
- so a(15) = 20,
     a(19) = 19,
     a(20) = 15.

Links

Crossrefs

See A360415 for a similar sequence.
Cf. A000119, A003714, A003754, A022290, A345101.

Programs

  • PARI
    See Links section.

Formula

a(A345101(n, k)) = A345101(n, A000119(n) + 1 - k).
a(A003754(n+1)) = A003714(n).
a(A003714(n)) = A003754(n+1).

A368577 Irregular table T(n, k), n >= 0, k = 1..A036497(n), read by rows; the n-th row lists the numbers m such that A331835(m) = n.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 8, 7, 9, 10, 16, 11, 12, 17, 13, 18, 14, 19, 20, 15, 21, 32, 22, 24, 33, 23, 25, 34, 64, 26, 35, 36, 65, 27, 28, 37, 66, 29, 38, 40, 67, 68, 30, 39, 41, 69, 128, 31, 42, 48, 70, 72, 129, 43, 44, 49, 71, 73, 130, 256, 45, 50, 74, 80, 131, 132, 257
Offset: 0

Views

Author

Rémy Sigrist, Dec 31 2023

Keywords

Comments

As a flat sequence, this is a permutation of the nonnegative integers (with inverse A368578).

Examples

			Table T(n, k) begins:
  n   n-th row
  --  ------------------
   0  0
   1  1
   2  2
   3  3, 4
   4  5
   5  6, 8
   6  7, 9
   7  10, 16
   8  11, 12, 17
   9  13, 18
  10  14, 19, 20
  11  15, 21, 32
  12  22, 24, 33
  13  23, 25, 34, 64
  14  26, 35, 36, 65
  15  27, 28, 37, 66
  16  29, 38, 40, 67, 68

Links

Crossrefs

Cf. A036497, A200947, A331835, A345101, A345297, A368578 (inverse).

Programs

  • PARI
    \\ See Links section.

Formula

T(n, 1) = A345297(n).
T(n, A036497(n)) = A200947(n).

A356974 Irregular triangle T(n, k) read by rows, n >= 0, k = 1..A117546(n); the n-th row contains the numbers m such that A356964(m) = n, in increasing order.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 32, 29, 33, 30, 34, 31, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 47, 49, 50, 51, 52, 53, 54, 55, 56, 64, 57, 65, 58, 66, 59, 67, 60, 68, 61, 69, 62, 70
Offset: 0

Views

Author

Rémy Sigrist, Sep 07 2022

Keywords

Comments

This sequence is to tribonacci numbers (A000073) what A345101 is to Fibonacci numbers (A000045).
This sequence (when interpreted as a flat sequence) is a permutation of the nonnegative integers.

Examples

			Triangle begins:
     0   [0]
     1   [1]
     2   [2]
     3   [3]
     4   [4]
     5   [5]
     6   [6]
     7   [7, 8]
     8   [9]
     9   [10]
    10   [11]
    11   [12]
    12   [13]
    13   [14, 16]
    14   [15, 17]

Links

Crossrefs

Cf. A000045, A000073, A003726, A003796, A117546 (row lengths), A345101, A356964.

Programs

  • PARI
    See Links section.

Formula

T(n, 1) = A003796(n+1).
T(n, A117546(n)) = A003726(n+1).
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.