A102965 - OEIS

A102965

Numbers n such that 3*10^n + R_n + 8 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

0, 3, 143, 797, 3143, 18791, 20763, 96743

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OFFSET

1,2

COMMENTS

Also numbers n such that (28*10^n+71)/9 is prime.

LINKS

FORMULA

a(n) = A101827(n-1) + 1.

MATHEMATICA

Do[ If[ PrimeQ[(28*10^n+71)/9], Print[n]], {n, 0, 10000}]

CROSSREFS

KEYWORD

more,nonn

AUTHOR

EXTENSIONS

Two more PRP terms from Serge Batalov, Nov 17 2008

Addition of a(8) from Kamada data by Robert Price, Dec 13 2010

STATUS

approved