OFFSET
1,1
COMMENTS
A number m is a term if and only if it has at least one non-infinitary divisor, or A000005(m) > A037445(m). - Vladimir Shevelev, Feb 23 2017
The asymptotic density of this sequence is 1 - A327839 = 0.3121728605... - Amiram Eldar, Jul 28 2020
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
MATHEMATICA
Select[Range@ 192, ! IntegerQ@ Log2@ DivisorSigma[0, #] &] (* Michael De Vlieger, Feb 24 2017 *)
PROG
(Haskell)
a162643 n = a162643_list !! (n-1)
a162643_list = filter ((== 0) . a209229 . a000005) [1..]
-- Reinhard Zumkeller, Nov 15 2012
(Python)
from itertools import count, islice
from sympy import factorint
def A162643_gen(startvalue=1): # generator of terms >= startvalue
return filter(lambda n:any(map(lambda m:((k:=m+1)&-k)^k, factorint(n).values())), count(max(startvalue, 1)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 08 2009
STATUS
approved