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A093167 Primes of the form 20*R_n + 7, where R_n is the repunit (A002275) of length n. 0
7, 227, 222222227, 222222222222227, 2222222222222222222222222227, 2222222222222222222222222222222222222222222222222222222222222227 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

LINKS

Makoto Kamada, Prime numbers of the form 22...227

CROSSREFS

Cf. A056677 (corresponding n and count of digits 2 in a(n)).

Sequence in context: A193503 A142606 A123832 * A157693 A142116 A201955

Adjacent sequences:  A093164 A093165 A093166 * A093168 A093169 A093170

KEYWORD

nonn,changed

AUTHOR

Rick L. Shepherd (rshepherd2(AT)hotmail.com), Mar 26 2004

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Last modified February 17 09:17 EST 2012. Contains 206009 sequences.