Williams primes of the form 9•10ⁿ+1

Current data

3, 4, 5, 9, 22, 27, 36, 57, 62, 78, 201, 537, 696, 790, 905, 1038, 66886, 70500, 91836, 100613, 127240, 380734, 583696, 719055, 823037, 862868

Remarks :

The sequence A056797 in OEIS
History at Studio Kamada
For all even n-values 9•10ⁿ+1 is a Generalized Fermat number.

2024-08-26: Checked n = 2 - 100000, Mark Rodenkirch, double-check, released
2024-08-22: Reserved by Mark Rodenkirch for n = 2 - 100000, double-check
2024-04-23: Checked n = 600000 - 1000000, Predrag Kurtovic
2024-04-22: Found n = 862868, Predrag Kurtovic
2024-04-22: Found n = 823037, Predrag Kurtovic
2024-04-18: Found n = 719055, Predrag Kurtovic
2020-06-30: Checked n = 500000 - 600000, Predrag Kurtovic
2020-06-25: Found n = 583696, Predrag Kurtovic
2020-06-22: Checked n = 400000 - 500000, Predrag Kurtovic
2019-09-30: Checked n = 350000 - 400000, Predrag Kurtovic
2019-09-18: Found n = 380734, Predrag Kurtovic
2018-07-08: Checked n = 300000 - 350000, Predrag Kurtovic
2018-06-17: Checked n = 250000 - 300000, Predrag Kurtovic
2018-05-25: Checked n = 124000 - 250000, Predrag Kurtovic
2015-01-22: Checked n = 1 - 200000, Robert Price
2015-01-21: Found n = 127240, Robert Price
2013-09-23: Checked n = 100000 - 124000, Predrag Kurtovic
2013-09-23: Found n = 100613, Predrag Kurtovic
2005-03-10: Found n = 70500, Peter Benson
2004-12-31: Found n = 66886, Peter Benson
2010-03-08: Checked n = 1 - 100000, Dmitry Domanov
1994: Found n = 1038, Harvey Dubner