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.

A333029 Order array of array A333028, read by antidiagonals.

Original entry on oeis.org

1, 2, 4, 3, 6, 10, 5, 8, 15, 11, 7, 12, 24, 18, 13, 9, 19, 38, 28, 21, 16, 14, 30, 58, 45, 32, 25, 17, 22, 47, 77, 65, 50, 40, 27, 20, 35, 67, 95, 84, 70, 60, 44, 31, 23, 55, 86, 112, 102, 89, 79, 64, 49, 36, 26, 74, 104, 128, 118, 106, 97, 83, 69, 56, 43
Offset: 1

Views

Author

Clark Kimberling, Mar 10 2020

Keywords

Comments

Suppose that (r(n,k)), for n >=1 and k >= 1 is an array of distinct numbers. Replace each r(n,k) by its position when all the numbers r(n,k) are ordered by <. The resulting array is the order array of (r(n,k)). The array A333029 is an interspersion and, as a sequence, a permutation of the natural numbers.

Examples

			Northwest corner:
   1   2   3   5   7    9   14   22
   4   6   8  12  19   30   47   67
  10  15  24  38  58   77   95  112
  11  18  24  45  65   84  102  118
  13  21  32  50  70   89  106  122
  16  25  40  60  79   97  114  130
  17  27  44  64  83  101  117  132
		

References

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

Crossrefs

Cf. A333028.

Programs

  • Mathematica
    W[n_, k_] := Fibonacci[k + 1] Floor[n*GoldenRatio] + (n - 1) Fibonacci[k];
    t = Table[GCD[W[n, 1], W[n, 2]], {n, 1, 500}];
    u = Flatten[Position[t, 1]] ; v[n_, k_] := W[u[[n]], k];
    g = Sort[Table[v[n - k + 1, k], {n, 20}, {k, n, 1, -1}] // Flatten]
    wo[n_, k_] := Length[Intersection[Range[v[n, k]], Complement[Range[1500], g]]]
    WP[n_, k_] := v[n, k] - wo[n, k];
    TableForm[Table[WP[n, k], {n, 1, 15}, {k, 1, 10}]]  (* A333029 array *)
    Table[WP[n - k + 1, k], {n, 16}, {k, n, 1, -1}] // Flatten  (* A333029 sequence *)