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 A337565 #9 Sep 17 2020 20:35:20 %S A337565 1,1,1,1,1,2,2,1,1,1,1,2,1,1,2,1,2,3,1,2,1,1,1,1,1,2,2,2,1,2,1,2,3,2, %T A337565 1,1,2,3,2,1,3,1,1,2,1,3,1,1,2,1,1,1,1,1,1,2,2,2,1,1,1,3,3,2,1,1,2,3, %U A337565 1,1,1,1,2,1,3,4,2,2,2,1,1,1,2,3,3 %N A337565 Irregular triangle read by rows where row k is the sequence of maximal anti-run lengths in the k-th composition in standard order. %C A337565 An anti-run is a sequence with no adjacent equal parts. %C A337565 A composition of n is a finite sequence of positive integers summing to n. The k-th composition in standard order (graded reverse-lexicographic, A066099) is obtained by taking the set of positions of 1's in the reversed binary expansion of k, prepending 0, taking first differences, and reversing again. This gives a bijective correspondence between nonnegative integers and integer compositions. %e A337565 The first column below lists various selected n; the second column gives the corresponding composition; the third column gives the corresponding row of the triangle, i.e., the anti-run lengths. %e A337565 1: (1) -> (1) %e A337565 3: (1,1) -> (1,1) %e A337565 5: (2,1) -> (2) %e A337565 7: (1,1,1) -> (1,1,1) %e A337565 11: (2,1,1) -> (2,1) %e A337565 13: (1,2,1) -> (3) %e A337565 14: (1,1,2) -> (1,2) %e A337565 15: (1,1,1,1) -> (1,1,1,1) %e A337565 23: (2,1,1,1) -> (2,1,1) %e A337565 27: (1,2,1,1) -> (3,1) %e A337565 29: (1,1,2,1) -> (1,3) %e A337565 30: (1,1,1,2) -> (1,1,2) %e A337565 31: (1,1,1,1,1) -> (1,1,1,1,1) %e A337565 43: (2,2,1,1) -> (1,2,1) %e A337565 45: (2,1,2,1) -> (4) %e A337565 46: (2,1,1,2) -> (2,2) %e A337565 47: (2,1,1,1,1) -> (2,1,1,1) %e A337565 55: (1,2,1,1,1) -> (3,1,1) %e A337565 59: (1,1,2,1,1) -> (1,3,1) %e A337565 61: (1,1,1,2,1) -> (1,1,3) %e A337565 62: (1,1,1,1,2) -> (1,1,1,2) %e A337565 63: (1,1,1,1,1,1) -> (1,1,1,1,1,1) %e A337565 For example, the 119th composition is (1,1,2,1,1,1), with maximal anti-runs ((1),(1,2,1),(1),(1)), so row 119 is (1,3,1,1). %t A337565 stc[n_]:=Differences[Prepend[Join@@Position[Reverse[IntegerDigits[n,2]],1],0]]//Reverse; %t A337565 Table[Length/@Split[stc[n],UnsameQ],{n,0,50}] %Y A337565 A000120 gives row sums. %Y A337565 A333381 gives row lengths. %Y A337565 A333769 is the version for runs. %Y A337565 A003242 counts anti-run compositions. %Y A337565 A011782 counts compositions. %Y A337565 A106351 counts anti-run compositions by length. %Y A337565 A329744 is a triangle counting compositions by runs-resistance. %Y A337565 A333755 counts compositions by number of runs. %Y A337565 All of the following pertain to compositions in standard order (A066099): %Y A337565 - Sum is A070939. %Y A337565 - Adjacent equal pairs are counted by A124762. %Y A337565 - Runs are counted by A124767. %Y A337565 - Strict compositions are A233564. %Y A337565 - Constant compositions are A272919. %Y A337565 - Patterns are A333217. %Y A337565 - Heinz number is A333219. %Y A337565 - Anti-runs are counted by A333381. %Y A337565 - Anti-run compositions are A333489. %Y A337565 - Runs-resistance is A333628. %Y A337565 - Combinatory separations are A334030. %Y A337565 Cf. A106356, A113835, A114994, A124767, A181819, A228351, A238279, A318928, A333216, A333627, A333630. %K A337565 nonn,tabf %O A337565 0,6 %A A337565 _Gus Wiseman_, Sep 07 2020