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 A336102 #20 Apr 08 2021 07:24:54 %S A336102 0,0,1,1,3,3,8,8,20,20,48,48,112,112,256,256,576,576,1280,1280,2816, %T A336102 2816,6144,6144,13312,13312,28672,28672,61440,61440,131072,131072, %U A336102 278528,278528,589824,589824,1245184,1245184,2621440,2621440,5505024,5505024,11534336 %N A336102 Number of inseparable multisets of size n covering an initial interval of positive integers. %C A336102 A multiset is separable if it has a permutation that is an anti-run, meaning there are no adjacent equal parts. %C A336102 Alternatively, a multiset is separable if its greatest multiplicity is greater than the sum of its remaining multiplicities plus one. %C A336102 Also the number of compositions of n whose greatest part is greater than the sum of its remaining parts plus one. For example, the a(2) = 1 through a(7) = 8 compositions are: %C A336102 (2) (3) (4) (5) (6) (7) %C A336102 (1,3) (1,4) (1,5) (1,6) %C A336102 (3,1) (4,1) (2,4) (2,5) %C A336102 (4,2) (5,2) %C A336102 (5,1) (6,1) %C A336102 (1,1,4) (1,1,5) %C A336102 (1,4,1) (1,5,1) %C A336102 (4,1,1) (5,1,1) %H A336102 Michael De Vlieger, <a href="/A336102/b336102.txt">Table of n, a(n) for n = 0..6625</a> %H A336102 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,4,0,-4). %F A336102 a(2*n) = a(2*n + 1) = A049610(n + 1). %F A336102 a(n) = 2^(n-1) - A336103(n). %F A336102 A001792 repeated for n > 1. _David A. Corneth_, Jul 09 2020 %F A336102 From _Chai Wah Wu_, Apr 07 2021: (Start) %F A336102 a(n) = 4*a(n-2) - 4*a(n-4) for n > 5. %F A336102 G.f.: x^2*(1 - x)*(x + 1)^2/(2*x^2 - 1)^2. (End) %e A336102 The a(2) = 1 through a(7) = 8 multisets: %e A336102 {11} {111} {1111} {11111} {111111} {1111111} %e A336102 {1112} {11112} {111112} {1111112} %e A336102 {1222} {12222} {111122} {1111122} %e A336102 {111123} {1111123} %e A336102 {112222} {1122222} %e A336102 {122222} {1222222} %e A336102 {122223} {1222223} %e A336102 {123333} {1233333} %t A336102 Table[Length[Join@@Permutations/@Select[IntegerPartitions[n],With[{mx=Max@@#},mx>1+Total[DeleteCases[#,mx,{1},1]]]&]],{n,0,15}] %t A336102 (* Second program: *) %t A336102 CoefficientList[Series[x^2*(1 - x) (x + 1)^2/(2 x^2 - 1)^2, {x, 0, 43}], x] (* _Michael De Vlieger_, Apr 07 2021 *) %Y A336102 The strong (weakly decreasing multiplicities) case is A025065. %Y A336102 The bisection is A049610. %Y A336102 The separable version is A336103. %Y A336102 Sequences covering an initial interval are A000670. %Y A336102 Anti-run compositions are A003242. %Y A336102 Anti-run patterns are A005649. %Y A336102 Separable partitions are A325534. %Y A336102 Inseparable partitions are A325535. %Y A336102 Inseparable factorizations are A333487. %Y A336102 Anti-run compositions are ranked by A333489. %Y A336102 Heinz numbers of inseparable partitions are A335448. %Y A336102 Cf. A001792, A019472, A052841, A106351, A124767, A269134, A292884, A335433, A335126, A335452, A335548. %K A336102 nonn %O A336102 0,5 %A A336102 _Gus Wiseman_, Jul 08 2020