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 A233510 #8 Dec 15 2013 12:33:53
%S A233510 1,6,34,82,226,687,3027,12387,28738,258627,1109487,2218978,13313877,
%T A233510 26627758,159766557,2929053434
%N A233510 Least number k such that the number of iterations of h(m) = (greatest prime divisor of m) - (least prime divisor of m) that map k to 0 is n; see Comments.
%C A233510 The domain of h is extended to include 1, with h(1) = 1 (as in Mathematica).
%C A233510 a(17) <= 51096502407. - _Donovan Johnson_, Dec 15 2013
%e A233510 h(6) = 3 - 2 = 1, and h(1) = 0, so a(2) = 6.
%t A233510 z = 1000000; h[n_] := h[n] = FactorInteger[n][[-1, 1]] - FactorInteger[n][[1, 1]]; t[n_] := t[n] = Drop[FixedPointList[h, n], -2]; Table[t[n], {n, 1, z}]; a = Table[Length[t[n]], {n, 1, z}]; f[n_] := First[Flatten[Position[a, n]]]; g = Table[f[n], {n, 1, 10}]
%Y A233510 Cf. A231813.
%K A233510 nonn,more
%O A233510 1,2
%A A233510 _Clark Kimberling_, Dec 11 2013
%E A233510 a(11)-a(16) from _Donovan Johnson_, Dec 15 2013