A093599 Composite numbers having an odd number of prime factors, all of which are distinct.

30, 42, 66, 70, 78, 102, 105, 110, 114, 130, 138, 154, 165, 170, 174, 182, 186, 190, 195, 222, 230, 231, 238, 246, 255, 258, 266, 273, 282, 285, 286, 290, 310, 318, 322, 345, 354, 357, 366, 370, 374, 385, 399, 402, 406, 410, 418, 426, 429, 430, 434, 435

Offset: 1

Author

Eric W. Weisstein, Apr 03 2004

Keywords

• nonn

Comments

First differs from A007304 at 2*3*5*7*11 = 2310, which is a(360) and thus beyond the tabulated range.

Subsequence of A030059. - Bill McEachen, Nov 06 2020

Links

• Carl R. White, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Prime Sums
• Wikipedia, Moebius function

Crossrefs

Cf. A007304, A030059.

Programs

Mathematica

Select[Range[435], MoebiusMu[ # ] == -1 && Not[PrimeQ[ # ]] &] (* Alonso del Arte, Jan 24 2005 *)

PARI

is(n)=my(f=factor(n)[,2]); #f>2 && #f%2==1 && vecmax(f)==1 \\ Charles R Greathouse IV, Oct 19 2015