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 A073168 #9 Jul 31 2017 03:33:06
%S A073168 1,5,9,9,9,15,16,17,18,17,25,19,21,27,31,26,21,22,21,35,38,31,35,31,
%T A073168 34,33,37,39,49,49,33,52,49,47,39,43,47,47,48,48,41,49,48,60,59,59,49,
%U A073168 52,58,58,63,71,75,65,65,67,71,79,75,81,84,77,65,69,72,72,67,69,61,65,65
%N A073168 a(n) = A007821(n) - A022449(n).
%C A073168 Values of commutator of A000040 and A002808 functions i.e., of prime() and composite().
%t A073168 c[n_Integer] := FixedPoint[n+PrimePi[ # ]+1&, n] Table[Prime[c[w]]-c[Prime[w]], {w, 1, 10000}];
%Y A073168 Cf. A000040, A002808, A007821, A022449.
%K A073168 nonn
%O A073168 1,2
%A A073168 _Labos Elemer_, Jul 19 2002