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 A319856 #5 Sep 30 2018 20:27:11
%S A319856 0,1,2,2,3,3,4,3,4,4,5,4,6,5,6,4,7,6,8,6,8,6,9,6,9,7,8,8,10,9,11,6,10,
%T A319856 8,12,9,12,9,12,9,13,12,14,10,12,10,15,9,16,12,14,12,16,12,15,12,16,
%U A319856 11,17,12,18,12,16,9,18,15,19,14,18,16,20,12,21,13
%N A319856 Maximum number that can be obtained by iteratively adding or multiplying together parts of the integer partition with Heinz number n until only one part remains.
%C A319856 The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).
%e A319856 a(30) = 9 because the maximum number that can be obtained starting with (3,2,1) is 3*(2+1) = 9.
%t A319856 ReplaceListRepeated[forms_,rerules_]:=Union[Flatten[FixedPointList[Function[pre,Union[Flatten[ReplaceList[#,rerules]&/@pre,1]]],forms],1]];
%t A319856 nexos[ptn_]:=If[Length[ptn]==0,{0},Union@@Select[ReplaceListRepeated[{Sort[ptn]},{{foe___,x_,mie___,y_,afe___}:>Sort[Append[{foe,mie,afe},x+y]],{foe___,x_,mie___,y_,afe___}:>Sort[Append[{foe,mie,afe},x*y]]}],Length[#]==1&]];
%t A319856 Table[Max[nexos[If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]]]],{n,100}]
%Y A319856 Cf. A000792, A001970, A048249, A056239, A066739, A066815, A070960, A201163, A319850, A318948, A318949, A319841, A319855.
%K A319856 nonn
%O A319856 1,3
%A A319856 _Gus Wiseman_, Sep 29 2018