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 A178438 #26 Jan 17 2019 13:44:08
%S A178438 2,6,16,42,47,62,109,191,221,509,3671,4229,4886,6967,12086
%N A178438 Numbers n such that 10^n - 83 is prime.
%C A178438 The next term, if one exists, is > 100000. - _Robert Price_, Apr 25 2011
%C A178438 See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99917".
%H A178438 Makoto Kamada, <a href="https://stdkmd.net/nrr/">List of near-repdigit-related prime numbers</a>
%H A178438 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>
%e A178438 10^6 - 83 = 999917 which is a prime number.
%t A178438 nMax=1000; Do[If[PrimeQ[10^n-83], Print[n]], {n, nMax}]
%o A178438 (PARI) is(n)=ispseudoprime(10^n-83) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y A178438 Cf. A108330, A108328.
%K A178438 more,nonn
%O A178438 1,1
%A A178438 _Robert Price_, Dec 21 2010
%E A178438 Example corrected by _Patrick De Geest_, Nov 28 2014