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.

A283734 Rank array, R, of the golden ratio, read by antidiagonals downwards.

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 6, 8, 10, 12, 9, 11, 14, 16, 19, 13, 15, 18, 21, 24, 28, 17, 20, 23, 26, 30, 34, 38, 22, 25, 29, 32, 36, 41, 45, 50, 27, 31, 35, 39, 43, 48, 53, 58, 63, 33, 37, 42, 46, 51, 56, 61, 67, 72, 78, 40, 44, 49, 54, 59, 65, 70, 76, 82, 88, 95, 47
Offset: 1

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Author

Clark Kimberling, Mar 16 2017

Keywords

Comments

Every row intersperses all other rows, and every column intersperses all other columns. The array is the dispersion of the complement of column 1; column 1 is given by r(n) = r(n-1) + 1 + L(n), where L = lower Wythoff sequence (A000201).

Examples

			The corner of R begins:
1    2    4    6    9    13    17    22
3    5    8    11   15   20    25    31
7    10   14   18   23   29    35    42
12   16   21   26   32   39    46    54
19   24   30   36   43   51    59    68
28   34   41   48   56   65    74    84
38   45   53   61   70   80    90    101
50   58   67   76   86   97    108   120
Let t = golden ratio = (1 + sqrt(5))/2; then R(i,j) = rank of (j,i) when all nonnegative integer pairs (a,b) are ranked by the relation << defined as follows: (a,b) << (c,d) if a + b*t < c + d*t, and also (a,b) << (c,d) if a + b*t = c + d*t and b < d.  Thus R(2,1) = 10 is the rank of (1,2) in the list (0,0) << (1,0) << (0,1) << (2,0) << (1,1) << (3,0) << (0,2) << (2,1) << (4,0) << (1,2).
		

Crossrefs

Cf. A001622, A255977 (row 1), A283733 (column 1), A000201, A087465.

Programs

  • Mathematica
    r = 40; r1 = 12;(*r=# rows of T,r1=# rows to show*);
    c = 40; c1 = 12;(*c=# cols of T,c1=# cols to show*);
    s[0] = 1; s[n_] := s[n] = s[n - 1] + 1 + Floor[n*GoldenRatio];
    u = Table[s[n], {n, 0, 400}] (* A283733 *)
    v = Complement[Range[Max[u]], u];
    f[n_] := v[[n]]; Table[f[n], {n, 1, 30}]
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1,
    Length[Union[list]]]; rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    w[i_, j_] := rows[[i, j]];
    TableForm[Table[w[i, j], {i, 1, r1}, {j, 1, c1}]]   (* A283734, array *)
    Flatten[Table[w[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A283734, sequence *)
    TableForm[Table[w[i, 1] + w[1, j] + (i - 1)*(j - 1) - 1, {i, 1, r1}, {j, 1, c1}]] (* A283734, array, by formula *)

Formula

R(i,j) = R(i,0) + R(0,j) + i*j - 1, for i>=1, j>=1.