Rising for the fifth straight session, the Sensex at the Bombay Stock Exchange gained 75 points, or 0.4 percent, to close at a fresh six-week high of 17,413, today. The Sensex rose amid encouraging initial reports of advance tax payments by frontline companies, and positive European markets. The Nifty at the National Stock Exchange added 25 points, or 0.5 percent, to 5,222. Stock markets in Japan, Hong Kong, Singapore and South Korea ended mixed.