A292922 Triangle read by rows: T(n,k) is the number of numbers <= primorial(n) with k prime factors, counted without multiplicity.

1, 4, 1, 16, 12, 1, 60, 116, 32, 1, 377, 1085, 745, 101, 1, 3323, 11172, 11534, 3735, 264, 1, 42518, 153752, 195801, 99914, 17808, 715, 1, 646580, 2464246, 3535748, 2314475, 667138, 69877, 1624, 1, 12285485, 48959467

Offset: 1

Author

Gionata Neri, Sep 26 2017

Keywords

• nonn
• tabl

Examples

			The triangle T(n, m) begins:
n\k   1     2     3     4     5     6
1:    1
2:    4     1
3:   16    12     1
4:   60   116    32     1
5:  377  1085   745   101     1
6: 3323 11172 11534  3735   264     1
		

Crossrefs

Cf. A001221.

Programs

PARI

a(n) = r=prod(i=1,n,prime(i)); for(s=1,n,k=sum(t=2,r,omega(t)==s) ; k)