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A093171
Primes of the form 80*R_k + 7, where R_k is the repunit (
A002275
) of length k.
4
7, 887, 8887, 888887, 888888887, 888888888887, 888888888888888888888888888888888888888888888888888888888888888888888887
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OFFSET
1,1
COMMENTS
Primes of the form (8*10^k - 17)/9. -
Vincenzo Librandi
, Nov 16 2010
LINKS
Table of n, a(n) for n=1..7.
Makoto Kamada,
Prime numbers of the form 88...887
.
Index entries for primes involving repunits
CROSSREFS
Cf.
A056695
(corresponding k),
A096846
.
Sequence in context:
A193342
A298301
A332187
*
A330295
A177908
A127102
Adjacent sequences:
A093168
A093169
A093170
*
A093172
A093173
A093174
KEYWORD
nonn
AUTHOR
Rick L. Shepherd
, Mar 26 2004
STATUS
approved
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Last modified March 29 08:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)