

A103000


Numbers n such that 4*10^n + 8*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.


2



0, 3, 4, 6, 10, 12, 18, 40, 48, 96, 106, 114, 144, 364, 618, 1090, 11370, 59454, 196684
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OFFSET

1,2


COMMENTS

Also numbers n such that (44*10^n+1)/9 is prime.


LINKS



FORMULA



MATHEMATICA

Do[ If[ PrimeQ[(44*10^n + 1)/9], Print[n]], {n, 0, 10000}]


CROSSREFS



KEYWORD

more,nonn


AUTHOR



EXTENSIONS

Addition of a(16)a(18) from Kamada data by Robert Price, Dec 10 2010


STATUS

approved



