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.

A098021 Positions of 0's in the zero-one sequence [nr+2r]-[nr]-[2r], where r=sqrt(2) and [ ]=floor; see A187967.

Original entry on oeis.org

5, 10, 17, 22, 29, 34, 39, 46, 51, 58, 63, 68, 75, 80, 87, 92, 99, 104, 109, 116, 121, 128, 133, 138, 145, 150, 157, 162, 169, 174, 179, 186, 191, 198, 203, 208, 215, 220, 227, 232, 237, 244, 249, 256, 261, 268, 273, 278, 285, 290, 297, 302, 307, 314, 319, 326
Offset: 1

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Author

Roger L. Bagula, Sep 09 2004

Keywords

Comments

Former definition was "Irrational rotation of the square root of 2 as an implicit sequence with an uneven Cantor cartoon." Replaced this with more precise definition from Clark Kimberling. - N. J. A. Sloane, Jan 30 2016

Crossrefs

Cf. A187967.

Programs

  • Magma
    [3*n+2*Floor(n*Sqrt(2)): n in [1..60]]; // Vincenzo Librandi, Dec 17 2015
    
  • Mathematica
    Table[7 Floor[n (Sqrt[2] - 1)] + 5 Floor[n (2 - Sqrt[2])] + 5, {n, 1000}] (* Miko Labalan, Dec 14 2015 *)
    Table[3*n + 2*Floor[n*Sqrt[2]], {n,1,100}] (* G. C. Greubel, Mar 27 2018 *)
  • PARI
    for(n=1,100, print1(3*n + 2*floor(n*sqrt(2)), ", ")) \\ G. C. Greubel, Mar 27 2018

Formula

a(n) = 7 * floor(n * (sqrt(2) - 1)) + 5 * floor(n * (2 - sqrt(2))) + 5. - Miko Labalan, Dec 14 2015
a(n) = 3*n + 2*floor(n*sqrt(2)). - G. C. Greubel, Mar 27 2018

Extensions

Edited and extended by Robert G. Wilson v, Sep 25 2004
Entry revised by N. J. A. Sloane, Jan 30 2016