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A102965
Numbers n such that 3*10^n + R_n + 8 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
1
0, 3, 143, 797, 3143, 18791, 20763, 96743
OFFSET
1,2
COMMENTS
Also numbers n such that (28*10^n+71)/9 is prime.
FORMULA
a(n) = A101827(n-1) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(28*10^n+71)/9], Print[n]], {n, 0, 10000}]
CROSSREFS
Sequence in context: A279923 A195937 A162363 * A278310 A195936 A323998
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Dec 17 2004
EXTENSIONS
Two more PRP terms from Serge Batalov, Nov 17 2008
Addition of a(8) from Kamada data by Robert Price, Dec 13 2010
STATUS
approved