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.

A183080 Tree generated by the Beatty sequence of 3-sqrt(2).

Original entry on oeis.org

1, 2, 3, 5, 4, 8, 7, 13, 6, 10, 12, 21, 11, 18, 20, 35, 9, 16, 15, 27, 19, 32, 33, 56, 17, 29, 28, 48, 31, 54, 55, 94, 14, 24, 25, 43, 23, 40, 42, 73, 30, 51, 50, 86, 52, 89, 88, 151, 26, 46, 45, 78, 44, 75, 76, 129, 49, 83, 85, 146, 87, 148, 149, 254
Offset: 1

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Author

Clark Kimberling, Dec 23 2010

Keywords

Comments

A permutation of the positive integers. See the note at A183079.

Examples

			First five rows:
1
2
3 5
4 8 7 13
6 10 12 21 11 18 20 35
		

Crossrefs

Programs

  • Mathematica
    a = {1, 2}; row = {a[[-1]]}; r = 3 - Sqrt[2]; s = r/(r - 1); Do[a = Join[a, row = Flatten[{Floor[#*{r, s}]} & /@ row]], {n, 5}]; a (* Ivan Neretin, Nov 09 2015 *)

Formula

Let L(n)=floor(n*r), U(n)=floor(n*s), where r=3-sqrt(2) and s=r/(r-1).
The tree-array T(n,k) is then given by rows: T(0,0) = 1; T(1,0) = 2; T(n,2j) = L(T(n-1),j); T(n,2j+1) = U(T(n-1),j); for j=0,1,...,2^(n-1)-1, n>=2.