%I
%S 1,2,4,5,11,16,22,24,110,232,557,566,888,1946,2610,3302,10214,41756,
%T 89160,120782
%N Numbers k such that 3*R_k + 10 is prime, where R_k = 11...1 is the repunit (A002275) of length n.
%C Also, numbers k such that (10^k + 29)/3 is prime.
%C Terms from Kamada data. Note Kamada does not recognize k=1 as 13 is a degenerate case of form AAA..ABA.
%C a(21) > 2.5*10^5.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/aaaba.htm">Nearrepdigit numbers of the form AA...AABA</a>.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/3/33343.htm#prime">Prime numbers of the form 33...3343</a>.
%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%e For k=4, 3*R_4 + 10 = 3333 + 10 = 3343 which is prime.
%t Select[Range[0, 250000], PrimeQ[(10^# + 29)/3] &]
%o (MAGMA) [n: n in [0..400]  IsPrime((10^n+29) div 3)]; // _Vincenzo Librandi_, Apr 11 2015
%Y Cf. A002275.
%K more,hard,nonn
%O 1,2
%A _Robert Price_, Apr 10 2015
