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 A305613 #6 Jun 06 2018 18:33:11 %S A305613 30,60,70,72,84,90,120,140,144,150,168,180,210,216,240,252,270,280, %T A305613 286,288,300,308,330,336,350,360,378,390,420,432,440,450,480,490,495, %U A305613 504,510,525,528,540,560,570,572,576,588,594,600,616,630,646,648,660,672 %N A305613 Numbers whose multiset of prime factors is not knapsack. %C A305613 A multiset of positive integers is knapsack if every distinct submultiset has a different sum. %e A305613 30 = 2 * 3 * 5 is not knapsack because 2 + 3 = 5. %t A305613 Select[Range[1000],DivisorSigma[0,#]=!=Length[Union[Total/@Subsets[Join@@Cases[FactorInteger[#],{p_,k_}:>Table[p,{k}]]]]]&] %Y A305613 Cf. A027746, A108917, A122768, A275972, A276024, A299701, A299729, A301855, A301900, A304793, A305611. %K A305613 nonn %O A305613 1,1 %A A305613 _Gus Wiseman_, Jun 06 2018