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A084761 Primes such that {a(m)-a(m-1)}/{a(m-1)-a(m-2)} is a unique integer. +0
1
2, 3, 5, 7, 13, 37, 157, 877, 6637, 46957, 530797, 4885357, 61494637, 684196717, 6911217517, 94089508717, 1576120459117, 23806584715117, 468415869835117, 11583647997835117, 211657826301835117, 3412844679165835117 (list; graph; listen)
OFFSET

0,1

COMMENT

The sequence of successive difference ratios {a(m)-a(m-1)}/{a(m-1)-a(m-2)} is 2,1,3,4,5,6,8,7,... Conjecture:(1) every number is a term of this sequence, or for every number r there exists some k such that {a(k) - a(k-1)}/{a(k-1)-a(k-2)}= r. Question: What is the longest string of consecutive integers in this sequence ( of successive differences)?

EXAMPLE

{a(5)-a(4)}/{a(4)-a(3) =(13-7)/(7-5) = 3. Then it is to be taken care of that this ratio is not 3 for any other set of three successive terms.

CROSSREFS

Sequence in context: A050779 A052291 A072826 this_sequence A038965 A055694 A007311

Adjacent sequences: A084758 A084759 A084760 this_sequence A084762 A084763 A084764

KEYWORD

nonn

AUTHOR

Amarnath Murthy and Meenakshi Srikanth (amarnath_murthy(AT)yahoo.com), Jun 17 2003

EXTENSIONS

More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Jan 06 2005

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Last modified July 24 12:00 EDT 2008. Contains 142294 sequences.


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