OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
EXAMPLE
For n=9, A001221({binomial(9,k)})={0,1,2,3,3,3,3,2,1,0} includes 4 distinct values. Therefore, a(9) = 4.
MATHEMATICA
Table[Length[Union[Table[PrimeNu[Binomial[n, k]], {k, 0, n}]]], {n, 1, 100}] (* G. C. Greubel, Apr 24 2017 *)
PROG
(PARI) a(n) = #Set(vector(n+1, k, omega(binomial(n, k-1)))); \\ Michel Marcus, May 14 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved