Generalized Cullen primes of the form `n`•3ⁿ+1

Current data

2^[1], 8, 32, 54^[2], 114^[3], 414^[4], 1400, 1850, 2848, 4874, 7268, 19290^[5], 337590^[6], 1183414, 1308596, 2220172, 9145334

Remarks :

The sequence A006552 in OEIS

2024-10-25: Checked n = 1 - 100000, Gary Barnes, double-check, released
2023-12-25: Found n = 9145334, Ryan Propper
2023-12-10: Checked n = 1200000 - 3000000, Mark Rodenkirch, released
2023-09-09: Checked n = 3000000 - 5000000, Ryan Propper
2023-09-04: Reserved by Ryan Propper for n = 3000000 - 5000000
2023-09-02: Found n = 2220172, Mark Rodenkirch
2023-07-23: Found n = 1308596, Mark Rodenkirch
2023-07-03: Reserved by Mark Rodenkirch to n = 3000000
2014: Checked n = 166800 - 1200000, Predrag Minovic
2014-01-20: Found n = 1183414, Predrag Minovic
2006-06-02: Found n = 337590, Predrag Minovic
2002: Checked n = 48949 - 166817, Günter Löh
2000: Checked n = 7781 - 48949, Wilfrid Keller
2000-01-26: Found n = 7268, Chun Wa Lau, missing prime found
1998-11-12: Found n = 7781-19290, Wilfrid Keller
1989: Checked n = 1 - 7781, Harvey Dubner
1989: Found n = 4874, Harvey Dubner
1989: Found n = 2848, Harvey Dubner