OFFSET
1,1
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Distinct Prime Factors.
Eric Weisstein's World of Mathematics, Prime Factor.
EXAMPLE
27 is in the sequence because 27 = 3^3 therefore omega(27) = 1 {3} is odd and bigomega(27) = 3 {3,3,3} is odd.
MATHEMATICA
Select[Range[220], Mod[PrimeNu[#1], 2] == Mod[PrimeOmega[#1], 2] == 1 & ]
Select[Range[300], AllTrue[{PrimeNu[#], PrimeOmega[#]}, OddQ]&] (* Harvey P. Dale, Jul 10 2023 *)
PROG
(PARI) is(k) = {my(f = factor(k)); omega(f) % 2 && bigomega(f) % 2; } \\ Amiram Eldar, Sep 17 2024
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Ilya Gutkovskiy, Dec 12 2016
STATUS
approved