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

1,2

Links

Table of n, a(n) for n=1..38.

Example

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

Prog

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

Crossrefs

Cf. A001221.

Sequence in context: A272279 A271413 A271262 * A117438 A075499 A367022

Adjacent sequences: A292919 A292920 A292921 * A292923 A292924 A292925

Keyword

nonn,tabl

Author

Gionata Neri, Sep 26 2017

Status

approved