You are absolutely right about the base current, screwed up the calculations with that one, however, I'd like to point out that most white LEDs will run happily @~3V (14-18mA), but you could indeed get higher intensity by using only three in series.
You are absolutely right about the base current, screwed up the calculations with that one, however, I'd like to point out that most white LEDs will run happily @~3V (14-18mA), but you could indeed get higher intensity by using only three in series.