OFFSET
2,1
COMMENTS
See A060344 for the corresponding result for Lie groups of type A_n.
LINKS
FORMULA
a(2) = 8, a(3) = 30 and a(n) = (n+5)*2^(n-1) for n >= 4.
G.f.: 2*x^2*(4-x-8*x^2-4*x^3)/(1-2*x)^2. a(n) = 4*(a(n-1)-a(n-2)) for n >= 6. [Colin Barker, Feb 10 2012]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Peter Bala, Jul 14 2007
STATUS
approved