# [seqfan] Re: A relation between A153971 and A098828?

Edwin Clark eclark at math.usf.edu
Wed Jan 7 15:43:49 CET 2009

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On Wed, 7 Jan 2009, Richard Mathar wrote:

>
> Are these two OEIS sequences tightly related:
>
> http://research.att.com/~njas/sequences/?q=id:A153971|id:A098828
>
> 11,23,59,83,179,263,311,419,479,683,839,1103,1511,2111,2243,2663,2963,3119,4139,4703,5099,5303,5939,7079,10223,11399,12011,12323,12959,17483,19403,21011,21839,22259,24419,25763,27143,27611,28559,30011,32003,
>
> 3,11,23,59,83,179,263,311,419,479,683,839,1103,1511,2111,2243,2663,2963,3119,4139,4703,5099,5303,5939,7079,10223,11399,12011,12323,12959,17483,19403,21011,21839,22259,24419,25763,27143,27611,28559,30011,
>

The sequence A153971 is incorrectly defined:

A153971 Numbers p such that 2^(p-1)+3 is not prime.
11, 23, 59, 83, 179, 263, 311, 419, 479, 683, 839, 1103, 1511,
2111, 2243, 2663, 2963, 3119, 4139, 4703, 5099, 5303, 5939, 7079, 10223,
11399, 12011, 12323, 12959, 17483, 19403, 21011, 21839, 22259, 24419,
25763, 27143, 27611, 28559, 30011, 32003

Note that if p = 6 then 2^(p-1)+3 = 35, but 6 is not in the
listed numbers. Next guess: definition should be only primes p such that
2^(p-1)+3 is not prime, but then 37 should be in the list, yet it is not.

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