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.

A103449 Values of k such that Sum_{m=0..k} Moebius(binomial(k,m)) = 0.

Original entry on oeis.org

3, 12, 24, 29, 34, 40, 54, 60, 67, 68, 75, 86, 93, 97, 102, 119, 125, 131, 133, 142, 152, 157, 160, 163, 164, 168, 170, 172, 189, 193, 197, 208, 210, 220, 221, 228, 229, 246, 251, 255, 257, 261, 270, 275, 280, 293, 296, 307, 308, 313, 315, 332, 337, 338, 340
Offset: 1

Views

Author

Emeric Deutsch, Feb 07 2005

Keywords

Comments

Values of k such that A103448(k) = 0.

Examples

			12 belongs to the sequence because the only squarefree values of binomial(12,m) are 1, 2*3*11, 2*3*11, 1, on which the Mobius function takes the values 1,-1,-1,1, respectively.
8 does not belong to the sequence because the only squarefree value of binomial(8,m) are 1, 2*5*7, 1, on which the Moebius function takes the values 1,-1,1, respectively.
		

Crossrefs

Programs

  • Mathematica
    A103448[n_]:= A103448[n]= Sum[MoebiusMu[Binomial[n, k]], {k, 0, n}];
    f:= Table[A103448[n], {n, 0, 1050}];
    Select[Range[0, 1000], f[[#]] == 0 &] - 1  (* G. C. Greubel, Jun 17 2021 *)
  • PARI
    is(k) = sum(m=0, k, moebius(binomial(k, m)))==0 \\ Felix Fröhlich, Jun 18 2021