A121537 If n appears then 2n, 3n and 4n do not.

1, 5, 6, 7, 8, 9, 11, 13, 17, 19, 23, 25, 29, 30, 31, 35, 37, 40, 41, 42, 43, 45, 47, 48, 49, 53, 54, 55, 56, 59, 61, 63, 64, 65, 66, 67, 71, 72, 73, 77, 78, 79, 81, 83, 85, 88, 89, 91, 95, 97, 99, 101, 102, 103, 104, 107, 109, 113, 114, 115, 117, 119, 121, 125, 127, 131

Offset: 1

Author

Zak Seidov, Aug 06 2006

Keywords

• nonn

Crossrefs

Cf. A003159 (if n appears then 2n does not), A036668 (if n appears then 2n and 3n do not).

Programs

Mathematica

s={1};Do[If[FreeQ[s,n/2]&&FreeQ[s,n/3]&&FreeQ[s,n/4],AppendTo[s,n]],{n,2,150}];s