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.

A344584 Difference between the inverse Möbius transform of the arithmetic derivative of n and the sum of the proper divisors of n: a(n) = A319684(n) - A001065(n).

Original entry on oeis.org

0, 0, 0, 2, 0, 1, 0, 10, 3, 1, 0, 11, 0, 1, 1, 34, 0, 13, 0, 15, 1, 1, 0, 47, 5, 1, 21, 19, 0, 12, 0, 98, 1, 1, 1, 59, 0, 1, 1, 67, 0, 14, 0, 27, 22, 1, 0, 151, 7, 21, 1, 31, 0, 76, 1, 87, 1, 1, 0, 82, 0, 1, 28, 258, 1, 18, 0, 39, 1, 16, 0, 203, 0, 1, 26, 43, 1, 20, 0, 219, 102, 1, 0, 104, 1, 1, 1, 127, 0, 99, 1, 51, 1, 1, 1, 423
Offset: 1

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Author

Antti Karttunen, May 24 2021

Keywords

Crossrefs

Inverse Möbius transform of A344178.

Programs

  • Mathematica
    Block[{a}, a[1] = 0; a[n_] := a[n] = If[n < 2, 0, n Total[#2/#1 & @@@ FactorInteger[n]]]; Array[DivisorSum[#, a[#] &] - DivisorSigma[1, #] + # &, 96]] (* Michael De Vlieger, May 24 2021 *)
  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A319684(n) = sumdiv(n, d, A003415(d));
    A344584(n) = (A319684(n) - (sigma(n)-n));

Formula

a(n) = A319684(n) - A001065(n) = A211991(n) + A319683(n).
a(n) = Sum_{d|n} A344178(d).
a(n) = n + Sum_{d|n} A168036(d).