A339911 Numbers k > 1 for which bigomega(k) <= bigomega(k-1)/2, where bigomega gives the number of prime factors, counted with multiplicity.

5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 33, 37, 41, 43, 47, 49, 53, 55, 57, 59, 61, 65, 67, 71, 73, 79, 82, 83, 85, 89, 91, 97, 101, 103, 107, 109, 113, 121, 127, 129, 131, 133, 137, 139, 141, 145, 149, 151, 157, 161, 163, 167, 169, 173, 177, 179, 181, 185, 191, 193, 197, 199, 201, 205, 209, 211, 217, 221, 223, 226, 227

Offset: 1

Author

Antti Karttunen, Dec 22 2020

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..17515; all terms <= 65537

Crossrefs

Cf. A001222.

Subsequence of A339910.

Cf. A339908, A339912 for subsequences.

Programs

Mathematica

Select[Range[3, 227, 2], PrimeOmega[#] <= PrimeOmega[# - 1]/2 &] (* Michael De Vlieger, Dec 22 2020 *)

PARI

isA339911(n) = ((n>1)&&((2*bigomega(n))<=bigomega(n-1)));