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A298867 Positions of numbers 4*p when all primes p and products 4*p are arranged in increasing order. 3
5, 7, 11, 13, 19, 21, 26, 29, 33, 40, 41, 46, 51, 53, 57, 63, 68, 71, 75, 81, 82, 87, 90, 95, 101, 105, 107, 110, 113, 117, 127, 131, 134, 135, 143, 146, 151, 156, 160, 165, 168, 170, 178, 180, 183, 184, 193, 202, 204, 206, 209, 214, 215, 222, 227, 233, 237 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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 products 4*p are 5,7,11,...

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, A298866 (complement).

Sequence in context: A314297 A108409 A291345 * A039681 A216746 A084441

Adjacent sequences:  A298864 A298865 A298866 * A298868 A298869 A298870

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Apr 14 2018

STATUS

approved

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Last modified September 28 00:46 EDT 2021. Contains 347698 sequences. (Running on oeis4.)