OFFSET
1,8
COMMENTS
The lowermost scatter plot gives an appearance of an elliptic galaxy seen from its side.
LINKS
PROG
(PARI)
up_to = 2310;
DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1])*sumdiv(n, d, if(d<n, v[n/d]*u[d], 0))); (u) }; \\ Compute the Dirichlet inverse of the sequence given in input vector v (correctly!)
A034386(n) = prod(i=1, primepi(n), prime(i));
A342002(n) = { my(s=0, m=1, p=2, e); while(n, e = (n%p); m *= p^(e>0); s += (e/p); n = n\p; p = nextprime(1+p)); (s*m); };
v346104 = DirInverseCorrect(vector(up_to, n, A342920(n)));
A346104(n) = v346104[n];
CROSSREFS
KEYWORD
sign,look
AUTHOR
Antti Karttunen, Jul 09 2021
STATUS
approved