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.

A366386 Excess of n when n is factored into factors q(i) = prime(i)/i: a(n) = A196050(n) - A324923(n).

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 1, 2, 2, 1, 0, 2, 1, 2, 2, 3, 1, 3, 2, 2, 2, 1, 2, 3, 3, 2, 4, 3, 1, 3, 0, 4, 2, 2, 2, 4, 2, 3, 3, 3, 1, 3, 2, 2, 4, 3, 2, 4, 4, 4, 2, 3, 3, 5, 3, 4, 3, 2, 1, 4, 3, 1, 4, 5, 3, 3, 2, 3, 4, 3, 2, 5, 2, 3, 5, 4, 2, 4, 1, 4, 6, 2, 2, 4, 2, 3, 3, 3, 3, 5, 3, 4, 2, 3, 3, 5, 3, 5, 4, 5, 2, 3, 4, 4, 4, 4, 3, 6
Offset: 1

Views

Author

Antti Karttunen, Oct 23 2023

Keywords

Crossrefs

Cf. A007097 (positions of 0's), A358731 (of 1's).
Cf. also A046660, A358729.

Programs

  • PARI
    A006530(n) = if(1==n, n, my(f=factor(n)); f[#f~, 1]);
    A366386(n) = { my(lista = List([]), gpf, i); while(n > 1, gpf=A006530(n); i = primepi(gpf); n /= gpf; n *= i; listput(lista,i)); #lista - #Set(lista); };

Formula

a(n) = A196050(n) - A324923(n).
a(n) <= A358729(n).