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Old 2010-11-04, 18:53   #1
science_man_88
 
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Default my misunderstanding of the OEIS

I find things like:

Cf. A126044-A126059. and I can't understand this as I tested it and it didn't come out to the sequence shown so i have no idea.
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Old 2010-11-04, 19:54   #2
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A000043 is list of prime p with 2^p-1 prime (= Mersenne prime) is:

2, 3, 5, 7, 13, 17, 19, 31, 61, 89,...

A126048 is A000043 mod 8:
2 (2 mod 8), 3 (3 mod 8), 5 (5 mod 8), 7 (7 mod 8), 5 (13 mod 8), 1 (17 mod 8), 3 (19 mod 8), 7 (31 mod 8), 5 (61 mod 8),...

Others the same.

Last fiddled with by kar_bon on 2010-11-04 at 19:54
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Old 2010-11-04, 21:17   #3
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Quote:
Originally Posted by kar_bon View Post
A000043 is list of prime p with 2^p-1 prime (= Mersenne prime) is:

2, 3, 5, 7, 13, 17, 19, 31, 61, 89,...

A126048 is A000043 mod 8:
2 (2 mod 8), 3 (3 mod 8), 5 (5 mod 8), 7 (7 mod 8), 5 (13 mod 8), 1 (17 mod 8), 3 (19 mod 8), 7 (31 mod 8), 5 (61 mod 8),...

Others the same.
Cf. A126043-A126059. I don't see how this would describe what you listed.
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Old 2010-11-04, 21:34   #4
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http://en.wikipedia.org/wiki/Cf.

Last fiddled with by axn on 2010-11-04 at 21:35
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Old 2010-11-04, 22:02   #5
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Quote:
Originally Posted by axn View Post
still don't completely understand but thanks for the link axn

Last fiddled with by science_man_88 on 2010-11-04 at 22:02
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Old 2010-11-05, 03:21   #6
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I don't understand what you don't understand, sm. I composed a post to answer you but didn't post it because it essentially duplicated what kar_bon posted.
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Old 2010-11-05, 11:51   #7
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Quote:
Originally Posted by CRGreathouse View Post
I don't understand what you don't understand, sm. I composed a post to answer you but didn't post it because it essentially duplicated what kar_bon posted.
all I've got so far is confer AX-AY is in cross reference but have no idea at all what it means literally as kar_bon has basically told be a description of the series a cross-reference is in and nothing to help me figure it out.
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Old 2010-11-05, 12:30   #8
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Cf. A126044-A126059 means there are sequences which all related to each other only differing in small cases:

A126044: A000043 mod 4
A126045: A000043 mod 5
A126046: A000043 mod 6
...
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Old 2010-11-05, 12:35   #9
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Quote:
Originally Posted by kar_bon View Post
Cf. A126044-A126059 means there are sequences which all related to each other only differing in small cases:

A126044: A000043 mod 4
A126045: A000043 mod 5
A126046: A000043 mod 6
...
see now that makes a bit more sense to me but then why list Adjacent sequences: A126040 A126041 A126042 this_sequence A126044 A126045 A126046 when most should be covered that other way ? anyway I get it now by the sounds of it.
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Old 2010-11-05, 15:52   #10
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The adjacent sequences don't mean very much unless you were trying to look up the sequence by hand instead of with the nice search tool.
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Old 2010-11-05, 15:54   #11
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Quote:
Originally Posted by kar_bon View Post
Cf. A126044-A126059 means there are sequences which all related to each other only differing in small cases
More generally, cf. means "compare": it shows a list of sequences which are in some way similar to the current one. They may not be as close as in this case, where they're all the same sequence with different choices of parameters.
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