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 A121840 #9 Oct 30 2018 10:31:02
%S A121840 15485863,32452843,49979687,67867967,86028121,104395301,122949823,
%T A121840 141650939,160481183,179424673,198491317,217645177,236887691,
%U A121840 256203161,275604541,295075147,314606869,334214459,353868013,373587883,393342739
%N A121840 (n*10^6)th prime.
%H A121840 Zak Seidov, <a href="/A121840/b121840.txt">Table of n, a(n) for n = 1..1000</a>
%F A121840 a(n)=A031922(1000n)=A000040(1000000n).
%t A121840 Table[Prime[1000000*n],{n,30}]
%o A121840 (PARI) a(n)=prime(10^6*n) \\ _Charles R Greathouse IV_, Nov 22 2011
%Y A121840 Cf. A000040, A031922.
%K A121840 nonn
%O A121840 1,1
%A A121840 _Zak Seidov_, Aug 29 2006