A060567 Number of binomial coefficients C(n,j) with j=0..n that are divisible by C(n,2).

3, 2, 1, 2, 2, 2, 4, 2, 2, 6, 5, 4, 10, 4, 2, 8, 10, 6, 12, 4, 6, 18, 10, 4, 14, 14, 6, 10, 23, 20, 22, 10, 18, 22, 10, 18, 34, 26, 15, 18, 24, 14, 32, 14, 10, 42, 28, 12, 28, 18, 12, 32, 34, 14, 25, 26, 42, 54, 30, 14, 58, 42, 22, 24, 28, 36, 60, 38, 20, 34, 44, 26, 70, 42, 20, 42

Offset: 2

Author

Labos Elemer, Apr 12 2001

Keywords

• nonn

Examples

			The relevant residues C(n,j) mod C(n,2) for n=16 are {1, 16, 0, 80, 20, 48, 88, 40, 30, 40, 88, 48, 20, 80, 0, 16, 1}, so a(16) = 2.
For n=227, there are only 6 nonzero residues; the residues are {1, 227, [111 zeros], 454, 454, [111 zeros], 227, 1}, so a(227) = 222.
		

Crossrefs

Cf. A060430, A014070.

Formula

a(n) = Cardinality{j | C(n,2) divides C(n,j), j=0..n}.