6 letter words:
auburn8,
5 letter words:
buran7,
unbar7,
urban7,
4 letter words:
barn6,
bran6,
buna6,
bura6,
burn6,
unau4,
3 letter words:
arb5,
ban5,
bar5,
bra5,
bun5,
bur5,
nab5,
nub5,
rub5,
urb5,
ran3,
run3,
urn3,
2 letter words:
ab4,
ba4,
an2,
ar2,
na2,
nu2,
un2,