OFFSET
1,2
COMMENTS
n divides a(n) for all n.
FORMULA
EXAMPLE
a(6) = (sigma(1)*pod(1)) * (sigma(2)*pod(2)) * (sigma(3)*pod(3)) * (sigma(6)*pod(6)) = (1*1) * (3*2) * (4*3) * (12*36) = 31104.
PROG
(Magma) [&*[&+ [c: c in Divisors(d)] * &*[c: c in Divisors(d)]: d in Divisors(n)]: n in [1..100]]
(PARI) a(n) = my(d=divisors(n)); prod(k=1, #d, my(dd=divisors(d[k])); vecsum(dd)*vecprod(dd)); \\ Michel Marcus, Apr 25 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Apr 25 2019
STATUS
approved