A230095 Odious numbers (A000069) that are the product of exactly two distinct primes.

14, 21, 22, 26, 35, 38, 55, 62, 69, 74, 82, 87, 91, 93, 94, 115, 118, 122, 133, 134, 143, 145, 146, 155, 158, 161, 185, 194, 203, 205, 206, 213, 214, 217, 218, 247, 253, 254, 259, 262, 265, 274, 295, 299, 301, 302, 309, 314, 319, 321, 327, 334, 339, 341, 346

Offset: 1

Author

N. J. A. Sloane, Oct 11 2013

Keywords

• nonn
• base

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
• E. Fouvry, C. Mauduit, Sommes des chiffres et nombres presque premiers, (French) [Sums of digits and almost primes] Math. Ann. 305 (1996), no. 3, 571--599. MR1397437 (97k:11029).

Crossrefs

Cf. A000069, A027697, A130593.

Programs

Mathematica

Select[Range[400],OddQ[DigitCount[#,2,1]]&&PrimeNu[#]==PrimeOmega[#]==2&] (* Harvey P. Dale, May 21 2024 *)

PARI

isodious(n)=b = binary(n); sum(i=1, #b, b[i]==1) % 2;
isok(n) = isodious(n) && (bigomega(n)==2) && (omega(n)==2); \\ Michel Marcus, Oct 12 2013

PARI

list(lim)=my(v=List()); forprime(p=2,lim\2, forprime(q=2,min(lim\p,p-1), if(hammingweight(p*q)%2, listput(v,p*q)))); Set(v) \\ Charles R Greathouse IV, Jan 31 2017

Extensions

More terms from Michel Marcus, Oct 12 2013