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.

A300725 Möbius transform of A053645(n), distance to the largest power of 2 less than or equal to n.

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 3, 0, 0, 1, 3, 2, 5, 3, 5, 0, 1, 0, 3, 2, 1, 3, 7, 4, 8, 5, 10, 6, 13, 5, 15, 0, -3, 1, -1, 0, 5, 3, 1, 4, 9, 1, 11, 6, 6, 7, 15, 8, 14, 8, 17, 10, 21, 10, 19, 12, 21, 13, 27, 10, 29, 15, 26, 0, -5, -3, 3, 2, -3, -1, 7, 0, 9, 5, -4, 6, 7, 1, 15, 8, 6, 9, 19, 2, 19, 11, 9, 12, 25, 6, 19, 14, 13, 15, 27
Offset: 1

Views

Author

Antti Karttunen, Mar 11 2018

Keywords

Crossrefs

Programs

  • Mathematica
    With[{s = Array[# - 2^Floor@ Log2@ # &, 95]}, Table[DivisorSum[n, MoebiusMu[n/#] s[[#]] &], {n, Length@ s}]] (* Michael De Vlieger, Mar 13 2018 *)
  • PARI
    A053644(n) = { my(k=1); while(k<=n, k<<=1); (k>>1); }; \\ From A053644
    A053645(n) = (n-A053644(n));
    A300725(n) = sumdiv(n,d,moebius(n/d)*A053645(d));

Formula

a(n) = Sum_{d|n} A008683(n/d)*A053645(d).
a(n) + A300724(n) = A000010(n).