The interail site says:
"You can buy an InterRail pass if your country of residence for at least 6 months has been:
one of the Inter Rail community members:
Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Finland, Former Yugoslavian Republic of Macedonia, France, Germany, Greece, Hungary, Ireland, Italy, Luxembourg, Montenegro, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom;
one of the other European countries:
Albania, Andorra, Belarus, Cyprus, Estonia, Faeroer, Gibraltar, Iceland, Latvia, Liechtenstein, Lithuania, Malta, Moldova, Monaco, Russia, San Marino, Ukraine, Vatican;
Train staff will check your residency in your travel document, so make sure that you bring the right documents.
Other Conditions
When buying the Inter Rail pass, you will have to show your identity card, passport or residence permit to prove your date of birth and country of residence."
Check with interail if you status as a student resident in Sweden for 6 months entitles you to use interail. You are more likely to have an informed answer from them.