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 A178531 #19 Jun 21 2023 17:18:54 %S A178531 2,3,4,5,6,7,11,57,61,70,127,223,237,240,310,467,651,1935,2333,3457, %T A178531 4456,6048,11289,12150,24693,28437,31123,32909,52041,58225,68297, %U A178531 201801 %N A178531 Numbers n such that 10^n - 93 is prime. %C A178531 a(33) > 3*10^5. %C A178531 See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99907" or "9w07". %H A178531 Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/">List of near-repdigit-related prime numbers</a>. %H A178531 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>. %e A178531 10^3 - 93 = 907 which is a prime number. %t A178531 m=1000; For[n=1, n<m, If[PrimeQ[10^n-93], Print[n]]; n++ ] %o A178531 (PARI) is(n)=ispseudoprime(10^n-93) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A178531 Cf. A108330, A108328. %K A178531 more,nonn %O A178531 1,1 %A A178531 _Robert Price_, Dec 23 2010 %E A178531 a(29-31) from _Robert Price_, May 29 2011 %E A178531 a(32) from _Robert Price_, Jun 21 2023