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 A375137 #13 Aug 11 2024 10:35:37 %S A375137 50,98,101,114,178,194,196,197,202,203,210,226,229,242,306,324,354, %T A375137 357,370,386,388,389,393,394,395,402,404,405,406,407,418,421,434,450, %U A375137 452,453,458,459,466,482,485,498,562,610,613,626,644,649,690,706,708,709 %N A375137 Numbers k such that the k-th composition in standard order (row k of A066099) matches the dashed pattern 1-32. %C A375137 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. %C A375137 These are also numbers k such that the maximal weakly increasing runs in the k-th composition in standard order do not have weakly decreasing leaders, where the leaders of weakly increasing runs in a sequence are obtained by splitting it into maximal weakly increasing subsequences and taking the first term of each. %C A375137 The reverse version (A375138) ranks compositions matching the dashed pattern 23-1. %H A375137 Wikipedia, <a href="https://en.wikipedia.org/wiki/Permutation_pattern">Permutation pattern</a>. %e A375137 Composition 102 is (1,3,1,2), which matches 1-3-2 but not 1-32. %e A375137 Composition 210 is (1,2,3,2), which matches 1-32 but not 132. %e A375137 Composition 358 is (2,1,3,1,2), which matches 2-3-1 and 1-3-2 but not 23-1 or 1-32. %e A375137 The terms together with corresponding compositions begin: %e A375137 50: (1,3,2) %e A375137 98: (1,4,2) %e A375137 101: (1,3,2,1) %e A375137 114: (1,1,3,2) %e A375137 178: (2,1,3,2) %e A375137 194: (1,5,2) %e A375137 196: (1,4,3) %e A375137 197: (1,4,2,1) %e A375137 202: (1,3,2,2) %e A375137 203: (1,3,2,1,1) %e A375137 210: (1,2,3,2) %e A375137 226: (1,1,4,2) %e A375137 229: (1,1,3,2,1) %e A375137 242: (1,1,1,3,2) %t A375137 stc[n_]:=Differences[Prepend[Join @@ Position[Reverse[IntegerDigits[n,2]],1],0]]//Reverse; %t A375137 Select[Range[0,100],MatchQ[stc[#],{___,x_,___,z_,y_,___}/;x<y<z]&] (*1-32*) %Y A375137 The complement is too dense, but counted by A189076. %Y A375137 The non-dashed version is A335480, reverse A335482. %Y A375137 For leaders of identical runs we have A335485, reverse A335486. %Y A375137 For identical leaders we have A374633, counted by A374631. %Y A375137 Compositions of this type are counted by A374636. %Y A375137 For distinct leaders we have A374768, counted by A374632. %Y A375137 The reverse version is A375138, counted by A374636. %Y A375137 For leaders of strictly increasing runs we have A375139, counted by A375135. %Y A375137 Matching 1-21 also gives A375295, counted by A375140 (complement A188920). %Y A375137 A003242 counts anti-runs, ranks A333489. %Y A375137 A011782 counts compositions. %Y A375137 A238130, A238279, A333755 count compositions by number of runs. %Y A375137 All of the following pertain to compositions in standard order: %Y A375137 - Length is A000120. %Y A375137 - Sum is A029837(n+1). %Y A375137 - Leader is A065120. %Y A375137 - Parts are listed by A066099, reverse A228351. %Y A375137 - Number of adjacent equal pairs is A124762, unequal A333382. %Y A375137 - Strict compositions are A233564. %Y A375137 - Constant compositions are A272919. %Y A375137 - Run-length transform is A333627, sum A070939. %Y A375137 - Run-counts: A124766, A124765, A124768, A124769, A333381, A124767. %Y A375137 - Run-leaders: A374629, A374740, A374683, A374757, A374515, A374251. %Y A375137 Cf. A056823, A106356, A188919, A238343, A333213, A373948, A373953, A374634, A374635, A374637, A375123, A375296. %K A375137 nonn %O A375137 1,1 %A A375137 _Gus Wiseman_, Aug 09 2024