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URL: https://oeis.org/A093401

⇱ A093401 - OEIS

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A093401
Primes of the form 20*R_k + 9, where R_k is the repunit (A002275) of length k.
2
29, 229, 22229, 22222222222229
OFFSET
1,1
COMMENTS
a(5) has 176 digits, a(6) has 416 digits. - Vincenzo Librandi, Dec 10 2010; Bruno Berselli, Jul 17 2012
CROSSREFS
Cf. A002275, A056678 (corresponding k), A099410.
Sequence in context: A091631 A244767 A146421 * A228408 A042636 A372962
KEYWORD
nonn
AUTHOR
Rick L. Shepherd, Mar 28 2004
STATUS
approved