Near repdigit primes on Numberphile - Page 5

Batalov · 2015-12-24, 23:31

No primes between n=70k and 102k, running up to ~~125k~~ 110k now.

Batalov · 2015-12-25, 19:35

There it is: 10^217218-10^108609-1 is prime.

paulunderwood · 2015-12-25, 20:00

Congrats, Serge and others who have helped. Will there be a "follow-up" video on Numberphile?

wombatman · 2015-12-25, 21:12

lavalamp · 2015-12-26, 02:34

Quote:

Originally Posted by Batalov

10^217218-10^108609-1 is prime.

Noice!

Quote:

Originally Posted by paulunderwood

Congrats, Serge and others who have helped. Will there be a "follow-up" video on Numberphile?

I doubt it, but you could go post it in the famously civil YouTube comment section.

paulunderwood · 2015-12-26, 03:39

Quote:

Originally Posted by lavalamp

I doubt it, but you could go post it in the famously civil YouTube comment section.

Done!

lavalamp · 2015-12-28, 06:13

The sieve from 20 to 100G is still running, but in the mean time I've run 100G to 128G on other CPUs. I have uploaded those factors here.

Batalov · 2015-12-28, 21:39

If anybody is interested to search for a(13), the region n>110,000 is free.
The note in OEIS is added.

wombatman · 2015-12-29, 16:46

I'll do n=110k to 120k (at least). Will keep going if nobody else takes a range.

lavalamp · 2016-01-03, 00:44

Here is the list of candidates for n<=10^6 sieved completely to 128*10^9.

10,226 additional candidates were removed between 20 and 128G. 131,029 candidates remain.

I do plan to do some more sieving in future, but do not have anything running at the moment.

wombatman · 2016-02-16, 14:13

I am pleased to report that n=132574 produces the 13th prime in the OEIS sequence for 10^(2n) - 10^n - 1!

Code:

Running N+1 test using discriminant 7, base 1+sqrt(7)
10^(2*132574)-10^132574-1 is prime! (6350.5180s+0.0065s)

The number has been reported to the OEIS sequence, and I will continue on.

2015-12-24, 23:31	#45
Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 9477₁₀ Posts	No primes between n=70k and 102k, running up to ~~125k~~ 110k now. Last fiddled with by Batalov on 2015-12-28 at 21:48 Reason: ( limit adjusted after finding a(12) )

2016-02-16, 14:13	#55
wombatman I moo ablest echo power! May 2013 29×61 Posts	Pleasant Surprise I am pleased to report that n=132574 produces the 13th prime in the OEIS sequence for 10^(2n) - 10^n - 1! Code: Running N+1 test using discriminant 7, base 1+sqrt(7) 10^(2*132574)-10^132574-1 is prime! (6350.5180s+0.0065s) The number has been reported to the OEIS sequence, and I will continue on.

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2015-12-25, 19:35	#46
Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 10010100000101₂ Posts	There it is: 10^217218-10^108609-1 is prime.

2015-12-25, 20:00	#47
paulunderwood Sep 2002 Database er0rr 3,739 Posts	Congrats, Serge and others who have helped. Will there be a "follow-up" video on Numberphile?

2015-12-25, 21:12	#48
wombatman I moo ablest echo power! May 2013 11011101001₂ Posts

2015-12-28, 21:39	#52
Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2505₁₆ Posts	If anybody is interested to search for a(13), the region n>110,000 is free. The note in OEIS is added.

2015-12-29, 16:46	#53
wombatman I moo ablest echo power! May 2013 1769₁₀ Posts	I'll do n=110k to 120k (at least). Will keep going if nobody else takes a range.