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A048687
a(n) is the number of classes generated by function A001221 when applied to binomial coefficients.
1
1, 2, 2, 3, 3, 2, 3, 4, 4, 4, 5, 4, 4, 4, 4, 5, 6, 5, 6, 6, 5, 6, 7, 5, 6, 6, 8, 8, 8, 6, 7, 9, 7, 9, 9, 8, 8, 9, 10, 8, 10, 8, 9, 11, 8, 9, 10, 9, 10, 10, 10, 9, 11, 10, 12, 11, 12, 11, 13, 11, 12, 12, 12, 13, 13, 12, 14, 13, 14, 12, 14, 13, 13, 13, 13, 13, 12, 15, 15, 14, 16, 14, 16, 14
OFFSET
1,2
LINKS
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
Sequence in context: A373888 A039645 A317993 * A308621 A308623 A115074
KEYWORD
nonn
AUTHOR
STATUS
approved