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 A330936 #4 Jan 05 2020 08:11:24 %S A330936 0,0,0,0,0,0,0,1,0,0,0,2,0,0,0,3,0,2,0,2,0,0,0,5,0,0,1,2,0,3,0,5,0,0, %T A330936 0,7,0,0,0,5,0,3,0,2,2,0,0,10,0,2,0,2,0,5,0,5,0,0,0,9,0,0,2,9,0,3,0,2, %U A330936 0,3,0,14,0,0,2,2,0,3,0,10,3,0,0,9,0,0 %N A330936 Number of nontrivial factorizations of n into factors > 1. %C A330936 The trivial factorizations of a number are (1) the case with only one factor, and (2) the factorization into prime numbers. %F A330936 For prime n, a(n) = 0; for nonprime n, a(n) = A001055(n) - 2. %e A330936 The a(n) nontrivial factorizations of n = 8, 12, 16, 24, 36, 48, 60, 72: %e A330936 (2*4) (2*6) (2*8) (3*8) (4*9) (6*8) (2*30) (8*9) %e A330936 (3*4) (4*4) (4*6) (6*6) (2*24) (3*20) (2*36) %e A330936 (2*2*4) (2*12) (2*18) (3*16) (4*15) (3*24) %e A330936 (2*2*6) (3*12) (4*12) (5*12) (4*18) %e A330936 (2*3*4) (2*2*9) (2*3*8) (6*10) (6*12) %e A330936 (2*3*6) (2*4*6) (2*5*6) (2*4*9) %e A330936 (3*3*4) (3*4*4) (3*4*5) (2*6*6) %e A330936 (2*2*12) (2*2*15) (3*3*8) %e A330936 (2*2*2*6) (2*3*10) (3*4*6) %e A330936 (2*2*3*4) (2*2*18) %e A330936 (2*3*12) %e A330936 (2*2*2*9) %e A330936 (2*2*3*6) %e A330936 (2*3*3*4) %t A330936 facs[n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[facs[n/d],Min@@#>=d&]],{d,Rest[Divisors[n]]}]]; %t A330936 Table[Length[DeleteCases[Rest[facs[n]],{_}]],{n,100}] %Y A330936 Positions of nonzero terms are A033942. %Y A330936 Positions of 1's are A030078. %Y A330936 Positions of 2's are A054753. %Y A330936 Nontrivial integer partitions are A007042. %Y A330936 Nontrivial set partitions are A008827. %Y A330936 Nontrivial divisors are A070824. %Y A330936 Cf. A001055, A003238, A005121, A317145, A317176, A318812, A330665, A330935. %K A330936 nonn %O A330936 1,12 %A A330936 _Gus Wiseman_, Jan 04 2020