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.

A356304 The least k >= 0 such that A003415(n) and A276086(n+k) are relatively prime, where A003415 is the arithmetic derivative, and A276086 is the primorial base exp-function.

Original entry on oeis.org

0, 0, 0, 0, 24, 0, 4, 3, 0, 0, 0, 0, 4, 1, 0, 0, 0, 0, 4, 9, 0, 0, 0, 5, 4, 3, 0, 0, 0, 0, 0, 177, 0, 1, 24, 0, 172, 1, 0, 0, 0, 0, 4, 3, 14, 0, 162, 161, 10, 9, 158, 0, 0, 1, 0, 1, 0, 0, 0, 0, 4, 3, 2, 1, 0, 0, 4, 1, 0, 0, 0, 0, 4, 15, 14, 1, 0, 0, 0, 3, 0, 0, 0, 1, 4, 1, 122, 0, 0, 1, 4, 1, 116, 1, 0, 0, 2212, 21
Offset: 2

Views

Author

Antti Karttunen, Nov 03 2022

Keywords

Crossrefs

Cf. A003415, A276086, A356311 (after its initial zero gives the positions of zeros in this sequence).
Cf. also A356302, A356305.

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A356304(n) = { my(k=0,x=A003415(n)); while(gcd(A276086(n+k),x)!=1,k++); (k); };