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.

A161627 Positions n such that A010060(n)=A010060(n+4).

Original entry on oeis.org

4, 5, 6, 7, 20, 21, 22, 23, 28, 29, 30, 31, 36, 37, 38, 39, 52, 53, 54, 55, 68, 69, 70, 71, 84, 85, 86, 87, 92, 93, 94, 95, 100, 101, 102, 103, 116, 117, 118, 119, 124, 125, 126, 127, 132, 133, 134, 135, 148, 149, 150, 151, 156, 157, 158, 159, 164, 165, 166, 167, 180, 181, 182
Offset: 1

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Author

Vladimir Shevelev, Jun 15 2009

Keywords

Comments

Or: union of the numbers of the form 4*A079523(n)+k, k=0, 1, 2, or 3.
Locates patterns of the form 1xxx1 or 0xxx0 in the Thue-Morse sequence.

Crossrefs

Programs

  • Mathematica
    tm[0] = 0; tm[n_?EvenQ] := tm[n] = tm[n/2]; tm[n_] := tm[n] = 1 - tm[(n-1)/2]; Reap[For[n = 0, n <= 200, n++, If[tm[n] == tm[n+4], Sow[n]]]][[2, 1]] (* Jean-François Alcover, Oct 24 2013 *)
    SequencePosition[ThueMorse[Range[200]],{x_,,,_,x_}][[All,1]] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Apr 16 2017 *)
  • PARI
    is(n)=hammingweight(n)%2==hammingweight(n+4)%2 \\ Charles R Greathouse IV, Aug 20 2013

Extensions

Extended by R. J. Mathar, Aug 28 2009