A321495 Numbers k such that k and k+1 have at least 5 but not both exactly 5 distinct prime factors.

728364, 1565564, 1774409, 1817529, 1923635, 2162094, 2187185, 2199834, 2225894, 2369850, 2557190, 2594514, 2659734, 2671305, 2794154, 2944689, 2964884, 3126045, 3139730, 3170244, 3244955, 3273809, 3279639, 3382379, 3387054, 3506810, 3555110, 3585945, 3686969, 3711630

Offset: 1

Author

M. F. Hasler, Nov 12 2018

Keywords

• nonn

Comments

Complement of A140079 (k and k+1 have exactly 5 distinct prime factors) in A321505 (k and k+1 have at least 5 distinct prime factors).

Crossrefs

Cf. A140079, A321505; A321494, A321496 (analog for 4 & 6 factors).

Programs

Mathematica

aQ[n_]:=Module[{v={PrimeNu[n],PrimeNu[n+1]}},Min[v]>4 && v!={5,5}]; Select[Range[120000], aQ] (* Amiram Eldar, Nov 12 2018 *)

PARI

is(n)=vecmin(n=[omega(n), omega(n+1)])>4&&n!=[5,5]

Formula

A321505 \ A140079.