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.

Showing 1-2 of 2 results.

A344439 a(n) = n - A206369(n).

Original entry on oeis.org

0, 1, 1, 1, 1, 4, 1, 3, 2, 6, 1, 6, 1, 8, 7, 5, 1, 11, 1, 8, 9, 12, 1, 14, 4, 14, 7, 10, 1, 22, 1, 11, 13, 18, 11, 15, 1, 20, 15, 20, 1, 30, 1, 14, 17, 24, 1, 26, 6, 29, 19, 16, 1, 34, 15, 26, 21, 30, 1, 36, 1, 32, 21, 21, 17, 46, 1, 20, 25, 46, 1, 37, 1, 38, 33, 22, 17, 54, 1, 36, 20, 42, 1, 48, 21, 44, 31, 38, 1, 62
Offset: 1

Views

Author

Antti Karttunen, May 23 2021

Keywords

Crossrefs

Programs

Formula

a(n) = n - A206369(n).
a(n) = A344440(n) - A344441(n).

A344441 a(n) = A061020(n) + abs(A061020(n)).

Original entry on oeis.org

2, 0, 0, 6, 0, 4, 0, 0, 14, 8, 0, 0, 0, 12, 16, 22, 0, 0, 0, 0, 24, 20, 0, 20, 42, 24, 0, 0, 0, 0, 0, 0, 40, 32, 48, 42, 0, 36, 48, 40, 0, 0, 0, 0, 0, 44, 0, 0, 86, 0, 64, 0, 0, 40, 80, 60, 72, 56, 0, 48, 0, 60, 0, 86, 96, 0, 0, 0, 88, 0, 0, 0, 0, 72, 0, 0, 120, 0, 0, 0, 122, 80, 0, 72, 128, 84, 112, 100, 0, 56, 144
Offset: 1

Views

Author

Antti Karttunen, May 23 2021

Keywords

Comments

a(k) = 0 for k in A026424. - David A. Corneth, May 23 2021

Crossrefs

Programs

  • Mathematica
    With[{nn = 91}, Map[# + Abs[#] &, Drop[CoefficientList[Series[Sum[LiouvilleLambda[k] k x^k/(1 - x^k), {k, 1, #}], {x, 0, #}], x], 1] &[nn]]] (* Michael De Vlieger, May 24 2021, after Jean-François Alcover at A061020 *)
  • PARI
    A061020(n) = {my(f=factorint(n)); prod(k=1, #f[, 2], ((-f[k, 1])^(f[k, 2]+1)-1)/(-f[k, 1]-1))};
    A344441(n) = { my(u=A061020(n)); (u+abs(u)); };

Formula

a(n) = A061020(n) + A206369(n) = A061020(n) + abs(A061020(n)).
a(n) = A344440(n) - A344439(n).
Showing 1-2 of 2 results.