<< KnotTheory`

Import["http://katlas.org/wiki/SubLink.m&action=raw"];

L=Link["L11a391"]

mva=MultivariableAlexander[L][t]

mva /. t[_] -> 1

Table[{
sub=SubLink[L, k],
Alexander[sub][t],
Simplify[mva/(((1-t[k])/(Sqrt[t[k]]))) /. t[i_] :> 1 /; i≠k]
}, {k,3}
]

Alexander[Knot[5,1]][t]

Alexander[Knot[5,1]][1]