cp's OEIS Frontend

A302594 Numbers whose prime indices other than 1 are equal prime numbers.

%I A302594 #4 Apr 10 2018 21:49:56
%S A302594 1,2,3,4,5,6,8,9,10,11,12,16,17,18,20,22,24,25,27,31,32,34,36,40,41,
%T A302594 44,48,50,54,59,62,64,67,68,72,80,81,82,83,88,96,100,108,109,118,121,
%U A302594 124,125,127,128,134,136,144,157,160,162,164,166,176,179,191,192
%N A302594 Numbers whose prime indices other than 1 are equal prime numbers.
%C A302594 A prime index of n is a number m such that prime(m) divides n.
%e A302594 Entry A302242 describes a correspondence between positive integers and multiset multisystems. In this case it gives the following sequence of set systems.
%e A302594 01: {}
%e A302594 02: {{}}
%e A302594 03: {{1}}
%e A302594 04: {{},{}}
%e A302594 05: {{2}}
%e A302594 06: {{},{1}}
%e A302594 08: {{},{},{}}
%e A302594 09: {{1},{1}}
%e A302594 10: {{},{2}}
%e A302594 11: {{3}}
%e A302594 12: {{},{},{1}}
%e A302594 16: {{},{},{},{}}
%e A302594 17: {{4}}
%e A302594 18: {{},{1},{1}}
%e A302594 20: {{},{},{2}}
%e A302594 22: {{},{3}}
%e A302594 24: {{},{},{},{1}}
%t A302594 primeMS[n_]:=If[n===1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
%t A302594 Select[Range[400],MatchQ[Union[DeleteCases[primeMS[#],1]],{_?PrimeQ}|{}]&]
%Y A302594 Cf. A000961, A001222, A003963, A005117, A006450, A007716, A056239, A076610, A275024, A047968, A281113, A295924, A301760, A302242, A302243.
%K A302594 nonn
%O A302594 1,2
%A A302594 _Gus Wiseman_, Apr 10 2018