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A048689 Number of classes generated by function A001222 when applied to binomial coefficients. 1
1, 2, 2, 2, 3, 3, 3, 3, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 7, 7, 8, 7, 7, 7, 8, 8, 8, 8, 9, 8, 9, 9, 10, 9, 10, 11, 10, 10, 11, 9, 10, 11, 11, 12, 12, 12, 12, 10, 12, 11, 12, 13, 11, 13, 14, 13, 12, 12, 13, 13, 14, 11, 14, 13, 14, 14, 12, 13, 16, 15, 14, 14, 15, 14, 16, 13, 17, 15, 14, 16 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = length(union(A001222(binomial(n,k)))), for 0 <= k <= n.

EXAMPLE

For n=9, A001222({C(9,k)}) = {0,2,4,4,4,4,4,4,2,0} includes 3 distinct values, thus generating 3 classes of k values: {0,9},{1,8} and {2,3,4,5,6,7}. So a(9)=3.

MATHEMATICA

Table[Length[Union[Table[PrimeOmega[Binomial[n, k]], {k, 0, n}]]], {n,

   1, 50}] (* G. C. Greubel, May 19 2017 *)

CROSSREFS

Cf. A000005, A001221, A007947, A001222.

Sequence in context: A127240 A097561 A162345 * A069923 A095840 A131343

Adjacent sequences:  A048686 A048687 A048688 * A048690 A048691 A048692

KEYWORD

nonn

AUTHOR

Labos Elemer

STATUS

approved

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Last modified January 17 16:53 EST 2019. Contains 319235 sequences. (Running on oeis4.)