A216600 Number of ways to write n as a product with all factors <= n/4.

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 3, 0, 1, 0, 2, 0, 0, 0, 4, 1, 0, 1, 2, 0, 2, 0, 5, 0, 0, 1, 6, 0, 0, 0, 5, 0, 2, 0, 2, 2, 0, 0, 9, 1, 2, 0, 2, 0, 4, 1, 5, 0, 0, 0, 8, 0, 0, 2, 9, 1, 2, 0, 2, 0, 3, 0, 13, 0, 0, 2, 2, 1, 2, 0, 10, 3, 0, 0, 8, 1, 0

Offset: 1

Author

Reinhard Zumkeller, Oct 01 2012

Keywords

• nonn

Comments

a(n) = A066032(n,floor(n/4)) for n > 3.

Examples

			a(40) = #{10*4, 10*2*2, 8*5, 5*4*2, 5*2*2*2} = 5;
a(41) = #{} = 0;
a(42) = #{7*6, 7*3*2} = 2;
a(43) = #{} = 0;
a(44) = #{11*4, 11*2*2} = 2;
a(45) = #{9*5, 5*3*3} = 2.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A001055, A028422, A216599, A216601, A216602.

Programs

Haskell

a216600 n | n <= 3    = 0
          | otherwise = a066032_tabl !! (n-1) !! (n `div` 4 - 1)