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A103091
Numbers n such that 8*10^n + 7*R_n + 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
2
1, 3, 6, 31, 36, 61, 117, 229, 339, 3165, 3958, 5277, 5343, 6079, 6535, 8485, 15084, 34537
OFFSET
1,2
COMMENTS
Also numbers n such that (79*10^n+11)/9 is prime.
a(19) > 10^5. - Robert Price, Oct 27 2015
FORMULA
a(n) = A101078(n) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(79*10^n + 11)/9], Print[n]], {n, 0, 10000}]
CROSSREFS
Sequence in context: A117805 A154135 A182274 * A186940 A376311 A101751
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Jan 19 2005
EXTENSIONS
a(17) from Kamada data by Robert Price, Dec 14 2010
a(18) from Erik Branger May 01 2013 by Ray Chandler, Aug 16 2013
STATUS
approved