1193*2^1696600-1 (510731 digits)

125*2^1963964-1 (591215 digits)

4003*2^1496871-1 (450607 digits)

4183*2^1568799-1 (472260 digits)

1029*2^1711100-1 (515096 digits)

Not yet a k=5 prime...lol
117*2^1618434-1 is prime! (487200 decimal digits) Time : 879.994 sec. from Second Megabit Prime Drive.

183*2^1618775-1 is prime! (487303 decimal digits) Time : 959.872 sec. from Second Megabit Prime Drive.

4049*2^1509104-1 (454290 digits)

1307*2^1716556-1 (516738 digits)

4079*2^1798192-1 (541314 digits)

1299*2^1721369-1 (518187 digits)