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 A334968 #10 Jun 04 2020 06:40:11 %S A334968 1,2,2,3,2,4,4,4,2,4,3,5,4,5,5,5,2,4,4,6,4,6,6,6,4,6,6,6,6,6,6,6,2,4, %T A334968 4,6,3,7,7,7,4,7,4,7,7,7,7,7,4,6,7,7,7,7,7,7,6,7,7,7,7,7,7,7,2,4,4,6, %U A334968 4,8,8,8,4,6,6,8,6,8,8,8,4,8,6,8,6,8,8 %N A334968 Number of possible sums of subsequences (not necessarily contiguous) of the n-th composition in standard order (A066099). %C A334968 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. %F A334968 a(n) = A299701(A333219(n)). %e A334968 The 139th composition is (4,2,1,1), with possible sums of subsequences {0,1,2,3,4,5,6,7,8}, so a(139) = 9. %e A334968 Triangle begins: %e A334968 1 %e A334968 2 %e A334968 2 3 %e A334968 2 4 4 4 %e A334968 2 4 3 5 4 5 5 5 %e A334968 2 4 4 6 4 6 6 6 4 6 6 6 6 6 6 6 %e A334968 2 4 4 6 3 7 7 7 4 7 4 7 7 7 7 7 4 6 7 7 7 7 7 7 6 7 7 7 7 7 7 7 %t A334968 stc[n_]:=Differences[Prepend[Join@@Position[Reverse[IntegerDigits[n,2]],1],0]]//Reverse; %t A334968 Table[Length[Union[Total/@Subsets[stc[n]]]],{n,0,100}] %Y A334968 Row lengths are A011782. %Y A334968 Dominated by A124771 (number of contiguous subsequences). %Y A334968 Dominates A333257 (the contiguous case). %Y A334968 Dominated by A334299 (number of subsequences). %Y A334968 Golomb rulers are counted by A169942 and ranked by A333222. %Y A334968 Positive subset-sums of partitions are counted by A276024 and A299701. %Y A334968 Knapsack partitions are counted by A108917 and ranked by A299702 %Y A334968 Knapsack compositions are counted by A325676 and ranked by A333223. %Y A334968 Contiguous subsequence-sums are counted by A333224 and ranked by A333257. %Y A334968 Knapsack compositions are counted by A334268 and ranked by A334967. %Y A334968 Cf. A000120, A029931, A048793, A066099, A070939, A108917, A325769, A325770, A325778, A334300, A335279. %K A334968 nonn,tabf %O A334968 0,2 %A A334968 _Gus Wiseman_, Jun 02 2020