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URL: https://oeis.org/A103093

⇱ A103093 - OEIS

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A103093
Numbers n such that 9*10^n + 2*R_n - 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
1
3, 4, 24, 39, 63, 76, 108, 166, 520, 1810, 2349, 2562, 5784, 6448, 11692, 16036, 17554
OFFSET
1,1
COMMENTS
Also numbers n such that (83*10^n-11)/9 is prime.
a(18) > 10^5. - Robert Price, Nov 03 2015
FORMULA
a(n) = A101001(n) + 1.
MATHEMATICA
Do[ If[ PrimeQ[(83*10^n - 11)/9], Print[n]], {n, 0, 10000}]
CROSSREFS
Sequence in context: A047180 A051394 A050801 * A124632 A048091 A189738
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Jan 19 2005
EXTENSIONS
a(15)-a(17) from Kamada data by Robert Price, Dec 14 2010
STATUS
approved