OFFSET
1,1
COMMENTS
T(n,k) = the smallest number m having exactly n prime divisors counted with multiplicity and exactly k distinct prime divisors.
LINKS
Eric Weisstein's World of Mathematics, Prime Factor
Eric Weisstein's World of Mathematics, Distinct Prime Factors
Eric Weisstein's World of Mathematics, Primorial
EXAMPLE
T(5,4) = 420 = 2^2*3*5*7, hence 420 is the smallest number m such that bigomega(m) = 5 and omega(m) = 4 (see A189982).
Triangle begins:
2;
4, 6;
8, 12, 30;
16, 24, 60, 210;
32, 48, 120, 420, 2310;
64, 96, 240, 840, 4620, 30030;
128, 192, 480, 1680, 9240, 60060, 510510;
...
MATHEMATICA
Flatten[Table[2^(n - k) Product[Prime[j], {j, k}], {n, 10}, {k, n}]]
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Ilya Gutkovskiy, Apr 26 2018
STATUS
approved