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 A064919 #9 Jun 19 2018 05:15:20
%S A064919 2,3,6,5,10,7,14,16,18,11,22,13,26,28,30,17,34,19,38,40,42,23,46,48,
%T A064919 50,52,54,29,58,31,62,64,66,68,70,37,74,76,78,41,82,43,86,88,90,47,94,
%U A064919 96,98,100,102,53,106,108,110,112,114,59,118,61,122,124,126,128,130,67
%N A064919 a(n) = Min { k | A064916(k) = n }.
%C A064919 A064916(a(n)) = n.
%H A064919 Harry J. Smith, <a href="/A064919/b064919.txt">Table of n, a(n) for n = 2..1000</a>
%F A064919 For n > 2: a(n) = if n is prime then n else 2*n - 2.
%o A064919 (PARI) lpf(n)= { local(f); f=factor(n); return(f[1, 1]) } { for (n=2, 1000, k=1; until (m==n, k++; L=lpf(k); m=k / L + L - 1); write("b064919.txt", n, " ", k) ) } \\ _Harry J. Smith_, Sep 29 2009
%Y A064919 Cf. A064916, A064923, A064924.
%K A064919 nonn
%O A064919 2,1
%A A064919 _Reinhard Zumkeller_, Oct 14 2001