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A102944
Numbers k such that 10^k + 8*R_k - 5 is prime, where R_k = 11...1 is the repunit (A002275) of length k.
1
1, 16, 22, 28, 34, 90, 2068, 2374, 2854, 3720, 4242, 22666, 29292, 29508
OFFSET
1,2
COMMENTS
Also numbers k such that (17*10^k - 53)/9 is prime.
a(15) > 10^5. - Robert Price, Feb 11 2015
FORMULA
a(n) = A102030(n) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(17*10^n - 53)/9], Print[n]], {n, 0, 10000}]
CROSSREFS
Sequence in context: A360735 A341169 A064804 * A058901 A059756 A242214
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Dec 16 2004
EXTENSIONS
Addition of a(12)-a(14) from Kamada data by Robert Price, Dec 12 2010
STATUS
approved