This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A183176 #29 May 11 2024 09:15:01
%S A183176 1,3,7,11,13,17,29,31,33,77,933,1555,11758,117707
%N A183176 Numbers k such that (10^(2k+1) + 12*10^k - 1)/3 is prime.
%C A183176 a(14) > 100000. - _Robert Price_, Dec 29 2016
%D A183176 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
%H A183176 Patrick De Geest, World!Of Numbers, <a href="http://www.worldofnumbers.com/wing.htm#pwp373">Palindromic Wing Primes (PWP's)</a>.
%H A183176 Makoto Kamada, <a href="https://stdkmd.net/nrr/3/33733.htm#prime">Prime numbers of the form 33...33733...33</a>.
%H A183176 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F A183176 a(n) = (A077790(n) - 1)/2.
%t A183176 Do[If[PrimeQ[(10^(2n + 1) + 12*10^n - 1)/3], Print[n]], {n, 3000}]
%o A183176 (PARI) is(n)=ispseudoprime((10^(2*n+1)+12*10^n-1)/3) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y A183176 Cf. A004023, A077775-A077798, A107123-A107127, A107648, A107649, A115073, A183174-A183187.
%K A183176 nonn,more,base
%O A183176 1,2
%A A183176 _Ray Chandler_, Dec 28 2010
%E A183176 a(14) from _Robert Price_, Oct 30 2023