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A093139
Primes of the form 10*R_k + 7, where R_k is the repunit (A002275) of length k.
1
7, 17, 1117, 11117, 11111117, 11111111111111111111117, 11111111111111111111111111117, 1111111111111111111111111111111111111117
OFFSET
1,1
COMMENTS
The next term has 131 digits. - Harvey P. Dale, Jul 05 2021
MATHEMATICA
Select[Table[FromDigits[PadLeft[{7}, n, 1]], {n, 50}], PrimeQ] (* Harvey P. Dale, Jul 05 2021 *)
CROSSREFS
Cf. A056655 (corresponding k).
Sequence in context: A013540 A153375 A001145 * A177366 A138491 A022511
KEYWORD
nonn
AUTHOR
Rick L. Shepherd, Mar 23 2004
STATUS
approved