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Old 2010-12-12, 21:00   #903
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Phi(4,2^7658614+1)/2

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1512500-82 is prime-in-progress.
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Old 2010-12-12, 21:06   #904
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Phi(4,2^7658614+1)/2

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(38ยท1017876-29)/9 is a prime (17877 digits)
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Old 2010-12-13, 10:03   #905
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Is anyone keeping track of compositorials?
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Old 2010-12-14, 01:16   #906
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Quote:
Originally Posted by lorgix View Post
Is anyone keeping track of compositorials?
The products of the first few composite numbers? Not that I'm aware of. You can get started on those.

Is that n!/n#?

Last fiddled with by 3.14159 on 2010-12-14 at 01:16
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Old 2010-12-14, 01:42   #907
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Quote:
Originally Posted by 3.14159 View Post
The products of the first few composite numbers? Not that I'm aware of. You can get started on those.

Is that n!/n#?
http://oeis.org/A036691 by the looks of it.

first result they don't have is :

101 3789610361627996838140194973640931105417226023081643585822775079629508916741315290850885175293649036474831772927007647018057857770220427674522746880000000000000000000000000000000

by the looks of it.

Last fiddled with by science_man_88 on 2010-12-14 at 02:02
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Old 2010-12-14, 04:26   #908
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If you like you can submit a b-file with more terms. I don't usually send in b-files for easy sequences unless there's special interest for some reason (for example, with plot2).

You may find this useful:
http://oeis.org/wiki/User:Charles_R_...g_with_b-files
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Old 2010-12-14, 06:30   #909
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Quote:
Originally Posted by 3.14159 View Post
The products of the first few composite numbers? Not that I'm aware of. You can get started on those.

Is that n!/n#?
I guess I could have been more clear; compositorial primes.

So; n!/n# +/- 1

Like

2967!/2967#-1 (7753digits)
2532!/2532#-1 (6453digits)

factordb has tables for n!/n# +/- 1
http://factorization.ath.cx/tables.php?open=8
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Old 2010-12-14, 13:45   #910
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Quote:
Originally Posted by lorgix View Post
I guess I could have been more clear; compositorial primes.

So; n!/n# +/- 1

Like

2967!/2967#-1 (7753digits)
2532!/2532#-1 (6453digits)

factordb has tables for n!/n# +/- 1
http://factorization.ath.cx/tables.php?open=8
http://oeis.org/A093155 is part of the -1 side.
http://oeis.org/search?q=2,5,193&sor...lish&go=Search is the best I can get for the +1 side

Last fiddled with by science_man_88 on 2010-12-14 at 13:46
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Old 2010-12-14, 16:15   #911
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Quote:
Originally Posted by lorgix View Post
I guess I could have been more clear; compositorial primes.
Ah. Those are indexed by Sloane's A049420 and A049421.
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Old 2010-12-14, 16:55   #912
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Quote:
Originally Posted by CRGreathouse View Post
Ah. Those are indexed by Sloane's A049420 and A049421.
Thanks.

Oh, so all smaller than 10000digits.

n= 3692 for the +1s, 3337 for the -1s.
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Old 2010-12-24, 07:22   #913
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Come on, that can't be it. Does anyone know any bigger ones?

Unrelated matter: Is anyone factoring 17^n+1?
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