OFFSET
1,2
COMMENTS
Numbers n such that A033273(n) divides n.
Fixed points of lcm(n, tau(n)-omega(n)), where tau(n) is the number of divisors of n (A000005) and omega(n) is the number of distinct primes dividing n (A001221).
All primes (A000040) are included in the sequence.
All even semiprimes (A100484) are included in the sequence.
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
EXAMPLE
12 is in the sequence because 12 has 6 divisors {1,2,3,4,6,12} out of which 4 are nonprimes {1,4,6,12} and 4 divides 12.
MATHEMATICA
Select[Range[150], Divisible[#1, DivisorSigma[0, #1] - PrimeNu[#1]] & ]
PROG
(PARI) isok(n) = denominator(n/sumdiv(n, d, !isprime(d))) == 1; \\ Michel Marcus, Dec 17 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Ilya Gutkovskiy, Dec 12 2016
STATUS
approved