OFFSET
1,2
COMMENTS
First differences of A053015. Since a(2) = 3 is prime, a(3) = 19679 is semiprime and a(4) has 6 prime factors. - Jonathan Vos Post, Dec 11 2005
FORMULA
Equally, 1-0, (2^2)-1, (3^3)^3 - 2^2, ((4^4)^4)^4 - (3^3)^3, ...
CROSSREFS
KEYWORD
nonn
AUTHOR
Daniel Kiteck, Dec 07 2005
STATUS
approved