A292922 - OEIS

%I #10 Sep 30 2017 06:20:12

%S 1,4,1,16,12,1,60,116,32,1,377,1085,745,101,1,3323,11172,11534,3735,

%T 264,1,42518,153752,195801,99914,17808,715,1,646580,2464246,3535748,

%U 2314475,667138,69877,1624,1,12285485,48959467

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

%e The triangle T(n, m) begins:

%e n\k   1     2     3     4     5     6

%e 1:    1

%e 2:    4     1

%e 3:   16    12     1

%e 4:   60   116    32     1

%e 5:  377  1085   745   101     1

%e 6: 3323 11172 11534  3735   264     1

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

%Y Cf. A001221.

%K nonn,tabl

%O 1,2

%A _Gionata Neri_, Sep 26 2017