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 A332273 #9 Mar 10 2020 00:29:48 %S A332273 1,4,2,3,4,3,3,3,2,4,3,2,3,4,2,3,3,3,3,4,2,3,4,3,2,3,3,3,4,2,3,4,3,3, %T A332273 3,2,3,4,3,2,4,3,3,3,3,3,4,2,3,3,3,3,3,3,3,4,2,3,3,3,3,3,2,4,3,2,3,3, %U A332273 3,4,2,3,4,3,2,4,3,3,3,3,2,4,3,3,3,3,3 %N A332273 Sizes of maximal weakly decreasing subsequences of A000002. %F A332273 a(n) = A000002(2*n - 2) + A000002(2*n - 1) for n > 1. %e A332273 The weakly decreasing subsequences begin: (1), (2,2,1,1), (2,1), (2,2,1), (2,2,1,1), (2,1,1), (2,2,1), (2,1,1), (2,1), (2,2,1,1), (2,1,1), (2,1), (2,2,1), (2,2,1,1). %t A332273 kolagrow[q_]:=If[Length[q]<2,Take[{1,2},Length[q]+1],Append[q,Switch[{q[[Length[Split[q]]]],q[[-2]],Last[q]},{1,1,1},0,{1,1,2},1,{1,2,1},2,{1,2,2},0,{2,1,1},2,{2,1,2},2,{2,2,1},1,{2,2,2},1]]] %t A332273 kol[n_Integer]:=Nest[kolagrow,{1},n-1]; %t A332273 Length/@Split[kol[40],#1>=#2&] %Y A332273 The number of runs in the first n terms of A000002 is A156253. %Y A332273 The weakly increasing version is A332875. %Y A332273 Cf. A000002, A001462, A013947, A013948, A088568, A288605, A296658, A329315, A329316, A329317, A329362. %K A332273 nonn %O A332273 1,2 %A A332273 _Gus Wiseman_, Mar 08 2020