A298864 Ranks of products 3*p when all primes p and products 3*p are jointly ranked.

4, 6, 9, 12, 16, 18, 22, 24, 28, 33, 35, 41, 43, 45, 49, 53, 57, 60, 65, 67, 68, 73, 76, 80, 86, 88, 90, 94, 95, 98, 106, 109, 113, 114, 121, 123, 128, 131, 134, 137, 140, 142, 148, 150, 152, 154, 162, 169, 172, 174, 176, 179, 181, 187, 191, 194, 196, 199

Offset

1,1

Links

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

Example

A105585 = ordered sequence of primes p and products 3*p:  2, 3, 5, 6, 7, 9, 11, 13, 15, 17, ... in which primes occupy ranks 4,6,9,11,...

Mathematica

z = 1000; u = Prime[Range[z]]; w = Take[Union[u, 3 u], z];
p[n_] := If[MemberQ[u, w[[n]]], 0, 1];
Take[w, z];  (* A105585 *)
t = Table[p[n], {n, 1, z}];
Flatten[Position[t, 0]];  (* A298863 *)
Flatten[Position[t, 1]];  (* A298864 *)

Crossrefs

Cf. A000040, A105585, A298863 (complement).

Sequence in context: A134678 A100915 A144922 * A310667 A317538 A310668

Adjacent sequences: A298861 A298862 A298863 * A298865 A298866 A298867

Keyword

nonn,easy

Author

Clark Kimberling, Feb 13 2018

Status

approved