

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
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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



