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 rogue 2017-08-14 14:54

[QUOTE=ericw;465329][url]https://oeis.org/A100289[/url]
Numbers n such that (1!)^2 + (2!)^2 + (3!)^2 +...+ (n!)^2 is prime.
a(19) = 32841 from Serge Batalov, Jul 29 2017[/QUOTE]

I'll probably leave that one alone. I haven't working on it.

 rogue 2017-08-15 14:59

Sieving completed a couple of days ago. I've tested to n=30000 and have verified known results. I should reach Serge's find by the end of the week.

 rogue 2017-08-18 15:02

I've tested to n=40000 and have verified known results.

 rogue 2017-08-23 12:50

I've tested to n=50000 and have verified known results, including Serge's find. Continuing.

 rogue 2017-08-31 16:37

I've tested to n=60000. No new PRPs.

 rogue 2017-09-14 02:07

I've tested to n=70000. No new PRPs.

 rogue 2017-09-18 15:22

I don't know how I missed this one. The 25th term is for n=59961 which is 260447 digits (if I calculated that correctly).

The search is around n=74000. I'm not certain how much further I'm going to search, but I have sieved to n=100000.

 rogue 2017-10-23 13:30

After a hiatus, I've tested to n=80000. No new PRPs.

 rogue 2017-11-15 15:05

Completed to 90000. No new PRPs. Continuing.

 CRGreathouse 2017-11-15 19:53

[QUOTE=rogue;468033]I don't know how I missed this one. The 25th term is for n=59961 which is 260447 digits (if I calculated that correctly).[/QUOTE]

Great! (I verified that it's 3-prp.) I see that you've added it to [url=https://oeis.org/A001272]A001272[/url].

 ericw 2017-11-20 14:02

[QUOTE=rogue;468033]I don't know how I missed this one. The 25th term is for n=59961 which is 260447 digits (if I calculated that correctly).[/QUOTE]

(Actually 260448 decimal digits.)

Congratulations again :)

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