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A128193 First differences of values of n for Cullen primes in A005849. 1
140, 4572, 1082, 816, 11885, 13796, 177, 27187, 31169, 171594, 98856, 120624, 872929, 4973720, 351333 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Carlos Rivera's Problem 50 is devoted to this topic. If we pair differences according to magnitude, we first obtain 177-140=37 a prime. This raises the question as to whether there are other such prime values.
LINKS
Carlos Rivera, Problem 50. Is there a Cullen prime Cn with n prime?, The Prime Puzzles and Problems Connection.
FORMULA
a(n) = A005849(n+1) - A005849(n). - Michel Marcus, Sep 27 2020
EXAMPLE
a(1)=140 because the first pair of n are 1 and 141. 141 - 1 = 140.
CROSSREFS
Sequence in context: A255775 A199831 A264310 * A061607 A223349 A282613
KEYWORD
nonn,more
AUTHOR
Enoch Haga, Feb 18 2007
EXTENSIONS
Offset 1 from Michel Marcus, Sep 27 2020
a(14)-a(15) added by Florian Baur, Sep 27 2020
STATUS
approved

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Last modified February 27 16:21 EST 2024. Contains 370378 sequences. (Running on oeis4.)