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A103076
Numbers n such that 8*10^n + 2*R_n + 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
1
0, 2, 20, 33, 62, 68, 86, 195, 524, 530, 657, 1874, 2198, 62072, 73076
OFFSET
1,2
COMMENTS
Also numbers n such that (74*10^n+43)/9 is prime.
a(16) > 10^5. - Robert Price, Oct 19 2015
FORMULA
a(n) = A101063(n-1) + 1, for n>1.
MATHEMATICA
Do[ If[ PrimeQ[(74*10^n + 43)/9], Print[n]], {n, 0, 10000}]
PROG
(PARI) for(n=0, 1e3, if(isprime((74*10^n+43)/9), print1(n", "))) \\ Altug Alkan, Oct 19 2015
CROSSREFS
Sequence in context: A061471 A112271 A201122 * A293029 A298761 A062133
KEYWORD
more,nonn
AUTHOR
Robert G. Wilson v, Jan 19 2005
EXTENSIONS
Inserted a(1)=0 and added a(14)-a(15) by Robert Price, Oct 19 2015
STATUS
approved