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A093939
Primes of the form 3*10^k + 7*R_k, where R_k is the repunit (
A002275
) of length k.
1
3, 37, 377777777777, 377777777777777777
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OFFSET
1,1
COMMENTS
a(5) has 774 digits, a(6) has 18156. -
Vincenzo Librandi
, Dec 10 2010
LINKS
Table of n, a(n) for n=1..4.
Makoto Kamada,
Prime numbers of the form 377...77
.
Index entries for primes involving repunits
.
CROSSREFS
Cf.
A002275
,
A056705
(corresponding k).
Sequence in context:
A176245
A122787
A241895
*
A129122
A345688
A002405
Adjacent sequences:
A093936
A093937
A093938
*
A093940
A093941
A093942
KEYWORD
nonn
AUTHOR
Rick L. Shepherd
, Apr 17 2004
STATUS
approved
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Last modified May 2 17:05 EDT 2024. Contains 372198 sequences. (Running on oeis4.)