

A298866


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


3



1, 2, 3, 4, 6, 8, 9, 10, 12, 14, 15, 16, 17, 18, 20, 22, 23, 24, 25, 27, 28, 30, 31, 32, 34, 35, 36, 37, 38, 39, 42, 43, 44, 45, 47, 48, 49, 50, 52, 54, 55, 56, 58, 59, 60, 61, 62, 64, 65, 66, 67, 69, 70, 72, 73, 74, 76, 77, 78, 79, 80, 83, 84, 85, 86, 88
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OFFSET

1,2


LINKS

Clark Kimberling, Table of n, a(n) for n = 1..1000


EXAMPLE

The joint ranking begins with 2,3,5,7,8,11,12,13,17,19,20, as in A298865, so that ranks occupied by primes are 1,2,3,4,6,7,8,10,...


MATHEMATICA

z = 200; u = Prime[Range[z]]; w = Take[Union[u, 4 u], z]; (* A298865 *)
p[n_] := If[MemberQ[u, w[[n]]], 0, 1];
t = Table[p[n], {n, 1, z}];
Flatten[Position[t, 0]] (* A298866 *)
Flatten[Position[t, 1]] (* A298867 *)


CROSSREFS

Cf. A000040, A298866, A298867 (complement).
Sequence in context: A125292 A101513 A153276 * A108408 A173905 A171581
Adjacent sequences: A298863 A298864 A298865 * A298867 A298868 A298869


KEYWORD

nonn,easy


AUTHOR

Clark Kimberling, Apr 14 2018


STATUS

approved



