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 A063905 #21 Mar 13 2023 11:50:08
%S A063905 2,2,3,3,3,5,5,5,5,5,7,7,7,7,7,7,7,11,11,11,11,11,11,11,11,11,11,11,
%T A063905 13,13,13,13,13,13,13,13,13,13,13,13,13,17,17,17,17,17,17,17,17,17,17,
%U A063905 17,17,17,17,17,17,17,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19
%N A063905 Each prime p appears p times.
%C A063905 a(A007504(k)) = prime(k) and a(A007504(k) + 1) = prime(k + 1) for k > 0, where prime = A000040.
%H A063905 Harry J. Smith, <a href="/A063905/b063905.txt">Table of n, a(n) for n=1,...,1000</a>
%e A063905 a(A007504(4)) = prime(4) = 7 = a(17) and a(18) = a(A007504(4)+1) = prime(4+1) = prime(5) = 11.
%t A063905 Flatten[Table[Prime[n], {n, 8}, {Prime[n]}]] (* _Alonso del Arte_, Sep 08 2011 based on _Robert G. Wilson v_'s program for A002024 *)
%t A063905 Table[PadRight[{},p,p],{p,Prime[Range[8]]}]//Flatten (* _Harvey P. Dale_, Mar 13 2023 *)
%o A063905 (PARI) { n=0; p=1; for (m=1, 10^9, p=nextprime(p+1); for (i=1, p, write("b063905.txt", n++, " ", p); if (n==1000, break)); if (n==1000, break) ) } \\ _Harry J. Smith_, Sep 02 2009
%o A063905 (Haskell)
%o A063905 a063905 n = a063905_list !! (n-1)
%o A063905 a063905_list =
%o A063905 concat $ zipWith ($) (map replicate a000040_list) a000040_list
%o A063905 -- _Reinhard Zumkeller_, Mar 18 2011
%Y A063905 Cf. A007504, A002024, A000040, A175944.
%K A063905 nonn,easy
%O A063905 1,1
%A A063905 _Reinhard Zumkeller_, Aug 30 2001