1057*2^594689-1 (179023 digits)

1403*2^359146-1
1459*2^373251-1
Are prime.

37850187375*2^469548-1 (141359 digits)

1075*2^588029-1 (177018 digits)

143*2^968622-1 (291587 digits)

1587*2^364520-1 (109735 digits)
1587*2^365549-1 (110045 digits)
1587*2^402941-1 (121301 digits)
1587*2^442185-1 (133115 digits)
1587*2^442424-1 (133187 digits)
1587*2^448493-1 (135014 digits)
1529*2^487800-1 (146846 digits)

For the records: Both k (1529 and 1587) have been tested for n=350-500k.

1409*2^408568-1 (122995 digits)
1423*2^444231-1 (133731 digits)
1427*2^391542-1 (117870 digits)
1427*2^409722-1 (123342 digits)
1511*2^459846-1 (138431 digits)

The above four k (1409, 1423, 1427, 1511) as well as 1477, 1481 and 1589 have all been tested for n=350-500k. For the latter three no primes were found.

4275*2^586352-1 (176514 digits)

1493*2^364348-1 is prime.

1345*2^611309-1 (184026 digits)

7605*2^454099-1 (136702 digits).

k=7605 tested up to 454.1 and moving on.