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.
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, 35, 38, 40, 43, 44, 46, 49, 50, 51, 53, 57, 58, 59, 62, 63, 64, 67, 68, 69, 70, 71, 73, 76, 77, 79, 80, 81, 83, 85, 86, 87, 88, 92, 93, 95, 97, 98, 99, 100, 103, 106
Offset: 1
Keywords
Examples
The sequence of terms together with their Matula-Goebel numbers begins: 1: o 2: (o) 3: ((o)) 4: (oo) 5: (((o))) 7: ((oo)) 8: (ooo) 9: ((o)(o)) 10: (o((o))) 11: ((((o)))) 14: (o(oo)) 16: (oooo) 17: (((oo))) 19: ((ooo)) 20: (oo((o))) 21: ((o)(oo)) 22: (o(((o)))) 23: (((o)(o))) 25: (((o))((o))) 27: ((o)(o)(o))
Links
Crossrefs
Programs
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Mathematica
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]]; qaQ[n_]:=And[And@@Table[!Divisible[n,x],{x,DeleteCases[primeMS[n],1]}],And@@qaQ/@primeMS[n]]; Select[Range[100],qaQ]