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 A123200 #11 May 10 2019 23:38:44
%S A123200 24,30,198,345,348,432,438,471,492,609,669,774,777,858,864,1032,1083,
%T A123200 1125,1218,1395,1536,1824,1914,1929,2088,2139,2301,2334,2376,2418,
%U A123200 2448,2460,2544,2763,2832,2970,3021,3297,3369,3384,3495,3528,3540,3633,3777
%N A123200 Numbers k such that 1000000*k-1 and 1000000*k+1 are twin primes.
%H A123200 Harvey P. Dale, <a href="/A123200/b123200.txt">Table of n, a(n) for n = 1..2000</a>
%e A123200 a(6) = 432 because 431999999 and 432000001 are primes.
%p A123200 a:=proc(n) if isprime(10^6*n-1)=true and isprime(10^6*n+1)=true then n else fi end: seq(a(n),n=1..4500); # _Emeric Deutsch_, Nov 16 2006
%t A123200 Select[Range[3800],AllTrue[#*10^6+{1,-1},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Nov 13 2017 *)
%Y A123200 Cf. A000040, A040040, A045753, A002822, A124065.
%K A123200 easy,nonn,less
%O A123200 1,1
%A A123200 _Jonathan Vos Post_, Nov 05 2006
%E A123200 More terms from _Emeric Deutsch_, Nov 16 2006