cp's OEIS Frontend

A302505 Numbers whose prime indices are squarefree and have disjoint prime indices.

%I A302505 #4 Apr 10 2018 21:48:30
%S A302505 1,2,3,4,5,6,8,10,11,12,13,15,16,17,20,22,24,26,29,30,31,32,33,34,40,
%T A302505 41,43,44,47,48,51,52,55,58,59,60,62,64,66,67,68,73,79,80,82,83,85,86,
%U A302505 88,93,94,96,101,102,104,109,110,113,116,118,120,123,124,127
%N A302505 Numbers whose prime indices are squarefree and have disjoint prime indices.
%C A302505 A prime index of n is a number m such that prime(m) divides n.
%e A302505 Entry A302242 describes a correspondence between positive integers and multiset multisystems. In this case it gives the following sequence of set multisystems.
%e A302505 01: {}
%e A302505 02: {{}}
%e A302505 03: {{1}}
%e A302505 04: {{},{}}
%e A302505 05: {{2}}
%e A302505 06: {{},{1}}
%e A302505 08: {{},{},{}}
%e A302505 10: {{},{2}}
%e A302505 11: {{3}}
%e A302505 12: {{},{},{1}}
%e A302505 13: {{1,2}}
%e A302505 15: {{1},{2}}
%e A302505 16: {{},{},{},{}}
%e A302505 17: {{4}}
%e A302505 20: {{},{},{2}}
%e A302505 22: {{},{3}}
%e A302505 24: {{},{},{},{1}}
%e A302505 26: {{},{1,2}}
%e A302505 29: {{1,3}}
%e A302505 30: {{},{1},{2}}
%e A302505 31: {{5}}
%e A302505 32: {{},{},{},{},{}}
%t A302505 primeMS[n_]:=If[n===1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
%t A302505 Select[Range[100],UnsameQ@@Join@@primeMS/@primeMS[#]&]
%Y A302505 Cf. A000961, A001222, A003963, A005117, A007716, A056239, A275024, A279790, A281113, A294788, A301750, A302242, A302243.
%K A302505 nonn
%O A302505 1,2
%A A302505 _Gus Wiseman_, Apr 09 2018