And what about the mother of them all, A007908, the "triangle of the gods", which starts 1,12,123,1234,12345,123456,...,1234567891011,... and should contain infinitely many primes. The GIMPS folks checked out to n=344869 but did not find a prime, and their search, see A007908, seems to have been abandoned. On Sat, Dec 7, 2019 at 4:04 PM Neil Sloane <njasloane@gmail.com> wrote:
James, Hans - remarkable work. I updated A053063.
Can you do a similar thing for the other sequence that Eric mentioned, A281254?
On Sat, Dec 7, 2019 at 3:45 PM Hans Havermann <gladhobo@bell.net> wrote:
JB: "The 121'st of the pendulum numbers (your sequence) is a 255 digit prime, per maple."
There's one more in the first ten thousand: @ 4489 digits, the 1399th. _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun