

A103108


Numbers n such that 9*10^n + 8*R_n  5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.


1



2, 3, 32, 42, 75, 368, 1392, 16350, 49101, 49689, 91839
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OFFSET

1,1


COMMENTS

Also numbers n such that (89*10^n53)/9 is prime.


LINKS



FORMULA



MATHEMATICA

Do[ If[ PrimeQ[(89*10^n  53)/9], Print[n]], {n, 0, 10000}]


CROSSREFS



KEYWORD

more,nonn


AUTHOR



EXTENSIONS

a(9)a(10) from Erik Branger May 01 2013 by Ray Chandler, Aug 17 2013


STATUS

approved



