cp's OEIS Frontend

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

%I A292922 #10 Sep 30 2017 06:20:12
%S A292922 1,4,1,16,12,1,60,116,32,1,377,1085,745,101,1,3323,11172,11534,3735,
%T A292922 264,1,42518,153752,195801,99914,17808,715,1,646580,2464246,3535748,
%U A292922 2314475,667138,69877,1624,1,12285485,48959467
%N A292922 Triangle read by rows: T(n,k) is the number of numbers <= primorial(n) with k prime factors, counted without multiplicity.
%e A292922 The triangle T(n, m) begins:
%e A292922 n\k   1     2     3     4     5     6
%e A292922 1:    1
%e A292922 2:    4     1
%e A292922 3:   16    12     1
%e A292922 4:   60   116    32     1
%e A292922 5:  377  1085   745   101     1
%e A292922 6: 3323 11172 11534  3735   264     1
%o A292922 (PARI) a(n) = r=prod(i=1,n,prime(i)); for(s=1,n,k=sum(t=2,r,omega(t)==s) ; k)
%Y A292922 Cf. A001221.
%K A292922 nonn,tabl
%O A292922 1,2
%A A292922 _Gionata Neri_, Sep 26 2017