OFFSET
1,2
LINKS
PROG
(PARI) a(n) = my (f=factor(n)); prod(i=1, #f~, prime(2*primepi(f[i, 1]) - 1)^f[i, 2])
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Rémy Sigrist, Sep 22 2018
STATUS
approved