Squarefree numbers having at least two prime factors that are in arithmetic progression.

6, 10, 14, 15, 21, 22, 26, 33, 34, 35, 38, 39, 46, 51, 55, 57, 58, 62, 65, 69, 74, 77, 82, 85, 86, 87, 91, 93, 94, 95, 105, 106, 111, 115, 118, 119, 122, 123, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 177, 178, 183, 185, 187, 194, 201

1

The first number having three prime factors is 105 = 3 * 5 * 7, the first term in S000919.

T. D. Noe, Plot of 1000 terms

T. D. Noe, Table of 1000 terms

Eric W. Weisstein, MathWorld: Arithmetic Progression

(Mma) t = {}; Do[f = FactorInteger[n]; If[Length[f] > 1 && Union[Transpose[f][[2]]] == {1} && Length[Union[Differences[Transpose[f][[1]]]]] == 1, AppendTo[t, n]], {n, 500}]; t

Cf. S000919.

nonn

T. D. Noe, Jul 19 2016