OFFSET
1,2
COMMENTS
Occurrences of primes: 3 (17, 23, 61) in first 80 terms.
EXAMPLE
For n = 4: 4th composite number is 9. 9 has 3 divisors (1,3,9), thus gcd(9,3) * 4 = 12.
MATHEMATICA
Composites := Select[Range[2, 110], ! PrimeQ[#] &]; Composite[n_] := Last[Take[Composites, n]]; Table[GCD[Composite[n], DivisorSigma[0, Composite[n]]] n, {n, Length[Composites]}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Carlos Eduardo Olivieri, Dec 27 2014
STATUS
approved