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 1-5 of 5 results.

A182801 Joint-rank array of the numbers j*r^(i-1), where r = golden ratio = (1+sqrt(5))/2, i>=1, j>=1, read by antidiagonals.

Original entry on oeis.org

1, 3, 2, 5, 6, 4, 7, 9, 11, 8, 10, 13, 16, 19, 14, 12, 18, 23, 28, 32, 25, 15, 21, 31, 39, 48, 54, 42, 17, 26, 36, 52, 66, 81, 89, 71, 20, 29, 44, 61, 86, 110, 134, 147, 117, 22, 34, 49, 73, 102, 141, 181, 221, 240, 193, 24, 38, 57, 82
Offset: 1

Views

Author

Clark Kimberling, Dec 04 2010

Keywords

Comments

Joint-rank arrays are introduced here as follows.
Suppose that R={f(i,j)} is set of positive numbers, where i and j range through countable sets I and J, respectively, such that for every n, then number f(i,j) < n is finite. Let T(i,j) be the position of f(i,j) in the joint ranking of all the numbers in R. The joint-rank array of R is the array T whose i-th row is T(i,j).
For A182801, f(i,j)=j*r^(i-1), where r=(1+sqrt(5))/2 and I=J={1,2,3,...}.
(row 1)=A020959; (row 2)=A020960; (row 3)=A020961.
(col 1)=A020956; (col 2)=A020957; (col 3)=A020958.
Every positive integer occurs exactly once in A182801, so that as a sequence it is a permutation of the positive integers.

Examples

			Northwest corner:
1....3....5....7...10...12...
2....6....9...13...18...21...
4...11...16...23...31...36...
8...19...28...39...52...61...
		

Crossrefs

Programs

  • Mathematica
    r=GoldenRatio;
    f[i_,j_]:=Sum[Floor[j*r^(i-k)],{k,1,i+Log[r,j]}];
    TableForm[Table[f[i,j],{i,1,16},{j,1,16}]] (* A182801 *)

Formula

T(i,j)=Sum{floor(j*r^(i-k)): k>=1}.

A182849 Joint-rank array of the numbers j*(i-1+r), where r = golden ratio = (1+sqrt(5))/2, and i>=1, j>=1, by antidiagonals.

Original entry on oeis.org

1, 3, 2, 6, 7, 4, 9, 13, 11, 5, 14, 19, 21, 16, 8, 18, 27, 31, 30, 22, 10, 23, 36, 43, 45, 39, 28, 12, 26, 44, 56, 61, 57, 50, 34, 15, 32, 52, 68, 78, 79, 73, 60, 40, 17, 37, 63, 83, 94, 101, 98, 87, 70, 47, 20, 42, 72, 96, 113, 124, 126, 118, 104, 82, 54, 24, 48
Offset: 1

Views

Author

Clark Kimberling, Dec 08 2010

Keywords

Comments

Joint-rank arrays are defined in the first comment at A182801. Every positive integer occurs exactly once, so that as a sequence, A182849 is a permutation of the positive integers.

Examples

			Northwest corner:
1....3....6....9...
2....7...13...19...
4...11...21...31...
5...16...30...45...
		

Crossrefs

Programs

  • Mathematica
    r=GoldenRatio;
    f[i_,j_]:=Sum[Floor[j*(i-1+r)/(k-1+r)],{k,1,1+r+j(i-1+r)}];
    TableForm[Table[f[i,j],{i,1,10},{j,1,10}]] (* A182849 *)

Formula

T(i,j)=SUM{floor(j*(i-1+r)/(k-1+r)): r=(1+sqrt(5))/2, k>=1} for i>=1, j>=1.

A182847 Joint-rank array of the numbers j*(i-1+r), where r=sqrt(3), i>=1, j>=1, by diagonals.

Original entry on oeis.org

1, 3, 2, 6, 7, 4, 10, 13, 11, 5, 14, 20, 21, 16, 8, 18, 27, 32, 30, 22, 9, 24, 36, 42, 44, 38, 26, 12, 29, 46, 55, 61, 58, 49, 33, 15, 34, 54, 69, 77, 78, 72, 59, 40, 17, 39, 64, 84, 95, 100, 98, 87, 70, 47, 19, 45, 73, 97, 113, 123, 124, 117, 103, 80
Offset: 1

Views

Author

Clark Kimberling, Dec 08 2010

Keywords

Comments

Joint-rank arrays are defined in the first comment at A182801.

Examples

			Northwest corner:
1....3....6...10...
2....7...13...20...
4...11...21...32...
5...16...30...44...
		

Crossrefs

Programs

  • Mathematica
    r=Sqrt[3];
    f[i_,j_]:=Sum[Floor[j*(i-1+r)/(k-1+r)],{k,1,1+r+j(i-1+r)}];
    TableForm[Table[f[i,j],{i,1,10},{j,1,10}]]

Formula

T(i,j)=sum(k>=1, floor( j*(i-1+r)/(k-1+r) ) ) where r=sqrt(3), for i>=1, j>=1.

A182848 Joint-rank array of the numbers j*(i-1+r), where r=sqrt(5), i>=1, j>=1, by antidiagonals.

Original entry on oeis.org

1, 4, 2, 8, 7, 3, 12, 14, 11, 5, 17, 22, 21, 16, 6, 24, 30, 33, 29, 20, 9, 28, 40, 45, 44, 38, 26, 10, 35, 51, 59, 61, 57, 47, 32, 13, 41, 60, 73, 80, 77, 69, 56, 37, 15, 49, 71, 88, 97, 101, 94, 84, 66, 43, 18, 55, 82, 103, 115, 124, 123, 113, 99, 76, 50, 19, 64
Offset: 1

Views

Author

Clark Kimberling, Dec 08 2010

Keywords

Comments

Joint-rank arrays are defined in the first comment at A182801.

Examples

			Northwest corner:
1....4....8...12...17...
2....7...14...22...30...
3...11...21...33...45...
5...16...29...44...61...
		

Crossrefs

Programs

  • Mathematica
    r=Sqrt[5];
    f[i_,j_]:=Sum[Floor[j*(i-1+r)/(k-1+r)],{k,1,1+r+j(i-1+r)}];
    TableForm[Table[f[i,j],{i,1,10},{j,1,10}]]

Formula

T(i,j) = Sum_{k>=1} floor(j*(i-1+r)/(k-1+r)), where r=sqrt(5).

A292956 Rectangular array by antidiagonals: T(n,m) = rank of n*(r+m) when all the numbers k*(r+h), where r = sqrt(2), k>=1, h>=0, are jointly ranked.

Original entry on oeis.org

1, 2, 3, 4, 7, 5, 6, 11, 13, 9, 8, 17, 21, 19, 12, 10, 23, 30, 32, 26, 16, 14, 29, 39, 46, 44, 35, 20, 15, 36, 50, 59, 61, 55, 42, 24, 18, 41, 62, 75, 81, 77, 67, 51, 28, 22, 49, 72, 90, 100, 102, 95, 82, 60, 33, 25, 56, 84, 106, 120, 128, 125, 113, 93, 69
Offset: 1

Views

Author

Clark Kimberling, Oct 04 2017

Keywords

Comments

This is the transpose of the array at A182846. Every positive integer occurs exactly once, so that as a sequence, this is a permutation of the positive integers. [Sequence reference corrected by Peter Munn, Aug 27 2022]

Examples

			Northwest corner:
1   2    4    6    8    10   14   15   18
3   7    11   17   23   29   36   41   49
5   13   21   30   39   50   62   72   84
9   19   32   46   59   75   90   106  124
12  26   44   61   81   100  120  142  165
The numbers k*(r+h), approximately:
(for k=1):   1.414   2.414   3.414 ...
(for k=2):   2.828   4.828   6.828 ...
(for k=3):   4.242   7.242   10.242 ...
Replacing each by its rank gives
1   2    4
3   7    11
5   13   21
		

Crossrefs

Cf. A182846.

Programs

  • Mathematica
    r = Sqrt[2]; z = 12;
    t[n_, m_] := Sum[Floor[1 - r + n*(r + m)/k], {k, 1, Floor[n + m*n/r]}];
    u = Table[t[n, m], {n, 1, z}, {m, 0, z}]; TableForm[u]  (* A292956 array *)
    Table[t[n - k + 1, k - 1], {n, 1, z}, {k, n, 1, -1}] // Flatten  (* A292956 sequence *)

Formula

T(n,m) = Sum_{k=1...[n + m*n/r]} [1 - r + n*(r + m)/k], where r=sqrt(2) and [ ]=floor.
Showing 1-5 of 5 results.