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.

A342026 Difference in the maximal prime exponents between the arithmetic derivative of A276086(n) and A276086(n) itself, which is the prime product form of primorial base expansion of n.

Original entry on oeis.org

-1, -1, 0, -1, -1, -1, 0, 2, 0, -1, -1, -1, 0, -1, -1, 2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 0, 0, -1, -1, 1, 0, 0, 0, -1, -1, -1, -1, 0, 0, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, -1, -1, -1, -1, -1, 0, -1, 1, -1, -1, -1, -1, -1, -1, -1, 4, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1
Offset: 1

Views

Author

Antti Karttunen, Mar 13 2021

Keywords

Crossrefs

Cf. A003415, A276086, A342005, A327860, A328114, A328310, A328391, A342006 (positions of nonnegative terms).
Cf. also A342016, A342019.

Programs

  • PARI
    A051903(n) = if((1==n), 0, vecmax(factor(n)[, 2]));
    A327860(n) = { my(s=0, m=1, p=2, e); while(n, e = (n%p); m *= (p^e); s += (e/p); n = n\p; p = nextprime(1+p)); (s*m); };
    A328391(n) = if(!n,n,A051903(A327860(n)));
    A328114(n) = { my(s=0, p=2); while(n, s = max(s, (n%p)); n = n\p; p = nextprime(1+p)); (s); };
    A342026(n) = (A328391(n) - A328114(n));

Formula

a(n) = A328310(A276086(n)) = A328391(n) - A328114(n).
a(n) = -1 iff A342005(n) = 1.