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A298864
Ranks of products 3*p when all primes p and products 3*p are jointly ranked.
2
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
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
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Feb 13 2018
STATUS
approved