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.

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A294649 a(n) = numerator(A206369(n))/n.

Original entry on oeis.org

1, 1, 2, 3, 4, 1, 6, 5, 7, 2, 10, 1, 12, 3, 8, 11, 16, 7, 18, 3, 4, 5, 22, 5, 21, 6, 20, 9, 28, 4, 30, 21, 20, 8, 24, 7, 36, 9, 8, 1, 40, 2, 42, 15, 28, 11, 46, 11, 43, 21, 32, 9, 52, 10, 8, 15, 12, 14, 58, 2, 60, 15, 2, 43, 48, 10, 66, 12, 44, 12, 70, 35, 72, 18, 14
Offset: 1

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Author

Michel Marcus, Nov 06 2017

Keywords

Comments

a(n) = 1 for n in A127724.

Crossrefs

Cf. A127724 (k-imperfect), A206369, A294650 (denominator).
A225679 is a subsequence (on squarefree indices). - Michel Marcus, Dec 22 2017

Programs

  • Mathematica
    (* b = A209369 *) b[n_] := n*DivisorSum[n, LiouvilleLambda[#]/# &];
    a[n_] := Numerator[b[n]/n];
    Array[a, 100] (* Jean-François Alcover, Dec 04 2017 *)
  • PARI
    rhope(p, e) = my(s=1); for(i=1, e, s=s*p + (-1)^i); s;
    rho(n) = my(f=factor(n)); prod(i=1, #f~, rhope(f[i, 1], f[i, 2]));
    a(n) = numerator(rho(n)/n);
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