This is on level 4-6. If you need to unlock this level, you can find the map in level 4-2. You may also need to beat level 4-1 to unlock level 4-2.
Thanks for WolfheartSpell for helping us find this artifact.
Level 4-1 (To unlock level 4-2):
LLLLL LRRRR RRDLR ULDR
Level 4-2 (Map):
RDLRD DRLUU RLDDR LULRD UURLD DRLUR LDRUR ULDRU LDLUR ULULD RDLDL ULURU LDLUD RURDL DRDRU RUR
Level 4-6 (Artifact 7):
DLRDL RURLD RLLUU DDRUL RDLUU RRDRU DDLLU ULLRR DURDR DDLUL RDLUU RDL
(Thanks to lucas1987 for catching a mistake)
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