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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 15 07:17 EDT 2021. Contains 343909 sequences. (Running on oeis4.)