Erasing initial losses, the BSE Sensex on Tuesday rose 149 points on buying at bargain levels as investors picked up heavyweights such as RIL and Infosys amid a firm trend in European markets.The 30-share index, which declined 108 points on Monday, touched the week's low in early trade on Tuesday. However, it bounced back to close over 149 points up at nearly 16,863.The broad-based National Stock Exchange index Nifty also rose 47 points to 5,064.