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 A324845 #6 Mar 19 2019 07:15:27 %S A324845 1,2,3,4,5,7,8,9,10,11,14,16,17,19,20,21,22,23,25,27,29,31,32,33,34, %T A324845 35,38,40,43,44,46,49,50,51,53,57,58,59,62,63,64,67,68,69,70,71,73,76, %U A324845 77,79,80,81,83,85,86,87,88,92,93,95,97,98,99,100,103,106 %N A324845 Matula-Goebel numbers of rooted trees where the branches of no non-leaf branch of any terminal subtree form a submultiset of the branches of the same subtree. %H A324845 Gus Wiseman, <a href="/A324845/a324845.png">The sequence of rooted trees whose Matula-Goebel numbers belong to A324845</a>. %e A324845 The sequence of terms together with their Matula-Goebel numbers begins: %e A324845 1: o %e A324845 2: (o) %e A324845 3: ((o)) %e A324845 4: (oo) %e A324845 5: (((o))) %e A324845 7: ((oo)) %e A324845 8: (ooo) %e A324845 9: ((o)(o)) %e A324845 10: (o((o))) %e A324845 11: ((((o)))) %e A324845 14: (o(oo)) %e A324845 16: (oooo) %e A324845 17: (((oo))) %e A324845 19: ((ooo)) %e A324845 20: (oo((o))) %e A324845 21: ((o)(oo)) %e A324845 22: (o(((o)))) %e A324845 23: (((o)(o))) %e A324845 25: (((o))((o))) %e A324845 27: ((o)(o)(o)) %t A324845 primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]]; %t A324845 qaQ[n_]:=And[And@@Table[!Divisible[n,x],{x,DeleteCases[primeMS[n],1]}],And@@qaQ/@primeMS[n]]; %t A324845 Select[Range[100],qaQ] %Y A324845 Cf. A000081, A007097, A290822, A306844, A318186. %Y A324845 Cf. A324694, A324738, A324744, A324749, A324754, A324759, A324765, A324768, A324838, A324842, A324844, A324846, A324847, A324849. %K A324845 nonn %O A324845 1,2 %A A324845 _Gus Wiseman_, Mar 18 2019