A double factorial prime is a prime number of the form , where is a double factorial.
is prime for , 4, 6, 8, 16, 26, 64, 82, 90, 118, 194, 214, 728, ... (OEIS A007749), the largest of which are summarized in the following table.
digits | discoverer | |
169,435 | S. Fukai (Jun. 5, 2015) | |
229,924 | S. Fukai (Jun. 5, 2015) | |
344,538 | S. Fukai (Apr. 21, 2016) |
is prime for , 1, 2, 518, 33416, 37310, 52608, 123998, ... (OEIS A080778), the largest of which are summarized in the following table.
digits | discoverer | |
112,762 | H. Jamke (Jan. 3, 2008) | |
288,864 | S. Fukai (Jun. 5, 2015) |