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 A321467 #12 Nov 13 2018 12:54:58 %S A321467 1,1,1,2,5,15,47,183,719,3329,14990,83798,393864,2518898 %N A321467 Number of factorizations of n! into factors > 1 that can be obtained by taking the block-products of some set partition of {2,3,...,n}. %C A321467 a(n) is the number of factorizations coarser than (2*3*...*n) in the poset of factorizations of n! into factors > 1, ordered by refinement. %e A321467 The a(1) = 1 through a(5) = 15 factorizations: %e A321467 () (2) (6) (24) (120) %e A321467 (2*3) (3*8) (2*60) %e A321467 (4*6) (3*40) %e A321467 (2*12) (4*30) %e A321467 (2*3*4) (5*24) %e A321467 (6*20) %e A321467 (8*15) %e A321467 (10*12) %e A321467 (3*5*8) %e A321467 (4*5*6) %e A321467 (2*3*20) %e A321467 (2*4*15) %e A321467 (2*5*12) %e A321467 (3*4*10) %e A321467 (2*3*4*5) %e A321467 For example, 10*12 = (2*5)*(3*4), so (10*12) is counted under a(5). %t A321467 sps[{}]:={{}};sps[set:{i_,___}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,___}]; %t A321467 Table[Length[Union[Sort/@Apply[Times,sps[Range[2,n]],{2}]]],{n,10}] %Y A321467 Dominated by A000110. %Y A321467 Cf. A001055, A066723, A157612, A242422, A265947, A317141, A317144, A317145, A317534, A321468, A321470, A321471, A321472, A321514. %K A321467 nonn,more %O A321467 0,4 %A A321467 _Gus Wiseman_, Nov 11 2018