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A298867 Positions of numbers 4*p when all primes p and products 4*p are arranged in increasing order.

%I A298867 #6 Apr 17 2018 18:32:28
%S A298867 5,7,11,13,19,21,26,29,33,40,41,46,51,53,57,63,68,71,75,81,82,87,90,
%T A298867 95,101,105,107,110,113,117,127,131,134,135,143,146,151,156,160,165,
%U A298867 168,170,178,180,183,184,193,202,204,206,209,214,215,222,227,233,237
%N A298867 Positions of numbers 4*p when all primes p and products 4*p are arranged in increasing order.
%H A298867 Clark Kimberling, <a href="/A298867/b298867.txt">Table of n, a(n) for n = 1..1000</a>
%e A298867 The joint ranking begins with 2,3,5,7,8,11,12,13,17,19,20, as in A298865, so that ranks occupied by products 4*p are 5,7,11,...
%t A298867 z = 200; u = Prime[Range[z]]; w = Take[Union[u, 4 u], z];  (* A298865 *)
%t A298867 p[n_] := If[MemberQ[u, w[[n]]], 0, 1];
%t A298867 t = Table[p[n], {n, 1, z}];
%t A298867 Flatten[Position[t, 0]]  (* A298866 *)
%t A298867 Flatten[Position[t, 1]]  (* A298867 *)
%Y A298867 Cf. A000040, A298866, A298866 (complement).
%K A298867 nonn,easy
%O A298867 1,1
%A A298867 _Clark Kimberling_, Apr 14 2018