OFFSET
1,4
LINKS
PROG
(PARI)
A122111(n) = if(1==n, n, my(f=factor(n), es=Vecrev(f[, 2]), is=concat(apply(primepi, Vecrev(f[, 1])), [0]), pri=0, m=1); for(i=1, #es, pri += es[i]; m *= prime(pri)^(is[i]-is[1+i])); (m));
A324121(n) = gcd(sigma(n), n*numdiv(n));
(PARI)
\\ Or as a standalone program:
A336314(n) = if(1==n, 1, my(f=factor(n), es=Vecrev(f[, 2]), is=concat(apply(primepi, Vecrev(f[, 1])), [0]), pri=0, d=1, s=1, x=1, p, e); for(i=1, #es, pri += es[i]; p = prime(pri); e = 1+is[i]-is[1+i]; d *= e; s *= ((p^e)-1)/(p-1); x *= (p^(e-1))); gcd(s, x*d));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 19 2020
STATUS
approved