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 A375297 #5 Aug 27 2024 09:14:32 %S A375297 0,0,0,0,0,0,0,0,0,1,6,21,68,199,545,1410,3530,8557,20255,46968, %T A375297 107135,240927,535379,1177435,2566618,5551456 %N A375297 Number of integer compositions of n matching both of the dashed patterns 23-1 and 1-32. %C A375297 Also the number of integer compositions of n whose leaders of maximal weakly increasing runs are not weakly decreasing and whose reverse satisfies the same condition. %H A375297 Wikipedia, <a href="https://en.wikipedia.org/wiki/Permutation_pattern">Permutation pattern</a>. %H A375297 Gus Wiseman, <a href="/A374629/a374629.txt">Sequences counting and ranking compositions by their leaders (for six types of runs)</a>. %e A375297 The a(0) = 0 through a(11) = 21 compositions: %e A375297 . . . . . . . . . (12321) (1342) (1352) %e A375297 (2431) (2531) %e A375297 (12421) (11342) %e A375297 (13231) (12431) %e A375297 (112321) (12521) %e A375297 (123211) (13241) %e A375297 (13421) %e A375297 (14231) %e A375297 (23132) %e A375297 (24311) %e A375297 (112421) %e A375297 (113231) %e A375297 (122321) %e A375297 (123212) %e A375297 (123221) %e A375297 (124211) %e A375297 (132311) %e A375297 (212321) %e A375297 (1112321) %e A375297 (1123211) %e A375297 (1232111) %t A375297 Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], MatchQ[#,{___,y_,z_,___,x_,___}/;x<y<z]&&MatchQ[#,{___,x_,___,z_,y_,___}/;x<y<z]&]],{n,0,15}] %Y A375297 For leaders of identical runs we have A332834. %Y A375297 For just one of the two conditions we have A374636, ranks A375137/A375138. %Y A375297 These compositions are ranked by A375407. %Y A375297 A003242 counts anti-runs, ranks A333489. %Y A375297 A011782 counts compositions. %Y A375297 A106356 counts compositions by number of maximal anti-runs. %Y A375297 A238130, A238279, A333755 count compositions by number of runs. %Y A375297 A274174 counts contiguous compositions, ranks A374249. %Y A375297 A335456 counts patterns matched by compositions. %Y A375297 Cf. A000041, A056823, A188920, A189076, A238343, A333213, A335514, A374631, A374632, A374635, A374681. %K A375297 nonn,more %O A375297 0,11 %A A375297 _Gus Wiseman_, Aug 23 2024