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A093403
Primes of the form 50*R_k + 9, where R_k is the repunit (
A002275
) of length k.
2
59, 55555559, 555555555559, 555555555555555559, 55555555555555555555555559, 55555555555555555555555555555559
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OFFSET
1,1
COMMENTS
Primes of the form (5*10^k + 31)/9. -
Vincenzo Librandi
, Nov 17 2010
LINKS
Table of n, a(n) for n=1..6.
Makoto Kamada,
Prime numbers of the form 55...559
.
Index entries for primes involving repunits
FORMULA
a(n) = (50*10^
A056687
(n) + 31)/9 = (5*10^
A099418
(n) + 31)/9.
CROSSREFS
Cf.
A056687
(corresponding k),
A099418
.
Sequence in context:
A178066
A191947
A188269
*
A087535
A058931
A092914
Adjacent sequences:
A093400
A093401
A093402
*
A093404
A093405
A093406
KEYWORD
nonn
AUTHOR
Rick L. Shepherd
, Mar 28 2004
EXTENSIONS
Edited by
Ray Chandler
, Feb 27 2012
STATUS
approved
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Last modified March 29 00:26 EDT 2024. Contains 371264 sequences. (Running on oeis4.)