# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a102963
Showing 1-1 of 1

%I A102963 #16 Jan 17 2019 13:44:07
%S A102963 0,1,7,8,11,14,19,32,41,53,61,133,157,239,1237,30254,34423,139289
%N A102963 Numbers n such that 2*10^n + 8*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
%C A102963 Also numbers n such that (26*10^n+1)/9 is prime.
%H A102963 Makoto Kamada, <a href="https://stdkmd.net/nrr/2/28889.htm#prime">Prime numbers of the form 288...889</a>.
%H A102963 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F A102963 a(n) = A101972(n-1) + 1.
%t A102963 Do[ If[ PrimeQ[(26*10^n + 1)/9], Print[n]], {n, 0, 10000}]
%Y A102963 Cf. A002275, A101972.
%K A102963 more,nonn
%O A102963 1,3
%A A102963 _Robert G. Wilson v_, Dec 17 2004
%E A102963 a(16)-a(18) from Kamada data by _Robert Price_, Dec 14 2010

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE