OFFSET
1,1
COMMENTS
The first of two consecutive numbers in A033942.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
27 = 3^3 and 28 = 2^2 * 7. Thus, 27 and 28 both have at least three prime factors. Thus, 27 is in this sequence.
MAPLE
R:= NULL: count:= 0: state:= 0:
for n from 1 while count < 100 do
if numtheory:-bigomega(n) >= 3 then
if state = 1 then R:= R, n-1; count:= count+1
else state:= 1
fi
else state := 0
fi
od:
R; # Robert Israel, Sep 16 2022
MATHEMATICA
Select[Range[1000], Total[Transpose[FactorInteger[#]][[2]]] >= 3 && Total[Transpose[FactorInteger[# + 1]][[2]]] >= 3 &]
PROG
(Python)
from sympy import factorint
def is033942(n): return sum(factorint(n).values()) > 2
def ok(n): return is033942(n) and is033942(n+1)
print([k for k in range(400) if ok(k)]) # Michael S. Branicky, Sep 10 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Tanya Khovanova, Sep 10 2022
STATUS
approved