OFFSET
1,2
EXAMPLE
a(3)=7, as there are 7 numbers <= prime(3)# = 2*3*5 = 30 having 3 prime factors: 8=2*2*2, 12=2*2*3, 18=2*3*3, 20=2*2*5, 27=3*3*3, 28=2*2*7 and 30=2*3*5.
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Nov 12 2002
EXTENSIONS
17271 from Sascha Kurz, Jan 04 2003
a(8)-a(11) from Donovan Johnson, Nov 15 2009
a(12) from Donovan Johnson, Jul 16 2011
STATUS
approved